Can you find area of the Yellow shaded region? | (Circles) |

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  • Опубликовано: 18 янв 2025

Комментарии • 70

  • @AmirgabYT2185
    @AmirgabYT2185 6 месяцев назад +6

    S=3√3-π≈2,06. First, pin me please

    • @PreMath
      @PreMath  6 месяцев назад +2

      Excellent!
      Thanks for sharing ❤️

  • @Alishbafamilyvlogs-bm4ip
    @Alishbafamilyvlogs-bm4ip 6 месяцев назад +4

    Nice sharing sir❤🎉❤

    • @PreMath
      @PreMath  6 месяцев назад

      Thanks for the feedback ❤️

  • @jimlocke9320
    @jimlocke9320 6 месяцев назад +2

    Other ways to compute the area of ΔABC: At about 6:40, we have the side lengths of ΔOAD. Using OD as the base and AD as the height, the area is (1/2)bh = (1/2)(1)(√3) = (√3)/2. ΔABC is composed of ΔOAD and 5 more triangles congruent to it, so has 6 times the area of ΔOAD , or 6(√3)/2 = 3√3.
    Alternatively, once the side of the equilateral triangle is found to be 2√3, one can apply the formula A = (√3)a²/4, where a is the equilateral triangle's side length. Here, a = 2√3, therefore a² = (2√3)² = 12 and A = (√3)(12)/4 = 3√3.

    • @AmiraldeGrasse
      @AmiraldeGrasse 6 месяцев назад +1

      This way no need tu use trigonometry…

    • @PreMath
      @PreMath  6 месяцев назад +1

      Thanks for sharing ❤️

  • @andrepiotrowski5668
    @andrepiotrowski5668 28 дней назад

    To calculate r, you don't need to resort to Pythagoras. The perpendicular to BC through A is a median, O is the intersection of the medians and divides the perpendicular in the ratio 2:1...

  • @Ibrahimfamilyvlog2097l
    @Ibrahimfamilyvlog2097l 6 месяцев назад +2

    Good sir ❤❤

    • @PreMath
      @PreMath  6 месяцев назад

      Thanks for the feedback ❤️

  • @marioalb9726
    @marioalb9726 6 месяцев назад +2

    Area and radius of big circle:
    A = πR² = 4π cm²
    R = √4 = 2 cm
    Chord / Side of equilateral triangle:
    c = 2R.cos30° = 2 . 2 . √3/2
    c = 2√3 cm
    Circular ring area :
    A = ¼.π.c² = ¼.π.(2√3)²
    A = 3π cm²
    Círcular segment area x 3:
    A = 3 . ½R²(α-sinα)
    A = 3 . ½. 2². (120° - sin 120°)
    A = 3 . 2,4567 cm² = 7,37 cm²
    Yellow area:
    A = A₁ - A₂ = 3π - 7,37
    A = 2,055 cm² ( Solved √ )

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @jamestalbott4499
    @jamestalbott4499 6 месяцев назад +1

    Thank you!

    • @PreMath
      @PreMath  6 месяцев назад

      You are very welcome!
      Thanks for the feedback ❤️

  • @himo3485
    @himo3485 6 месяцев назад +2

    R*R*π=4π R=2
    radius of smaller circle : r r=R/2=2/2=1 smaller circle area = 1*1*π=π
    √]2²-1²]=√3 △ABC=2√3*3*1/2=3√3
    Yellow area = 3√3 - π

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @raya.pawley3563
    @raya.pawley3563 6 месяцев назад +1

    Thank you

    • @PreMath
      @PreMath  6 месяцев назад

      You are very welcome!
      Thanks for the feedback ❤️

  • @thewolfdoctor761
    @thewolfdoctor761 6 месяцев назад +1

    I did it the same way except I calculated the area of triangle BAC to be 6 * area of small triangle AOD = 6* (1/2)*(SQRT(3)*1) = 3*SQRT(3)

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @marcgriselhubert3915
    @marcgriselhubert3915 6 месяцев назад +2

    Be c the side length of the triangle ABC, R = 2 the radius of the big circle and H the orthogonal projection of a on (BC).
    We have 2 = R = (2/3).OH, so OH = 3
    3 = OH = (sqrt(3)/2).c, so c = 6/sqrt(3) = 2.sqrt(3)
    The area of ABC is (c^2).(sqrt(3)/4) = 3.sqrt(3)
    the radius of the little circle is OH =(1/2).OA = R/2 = 1
    The area inside the little circle is then Pi and finally the yellow area is 3.sqrt(3) - Pi. (No difficulty)

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @georgebliss964
    @georgebliss964 6 месяцев назад +2

    After the preliminaries.
    Triangle AOD.
    Angle AOD = 60 degrees.
    So sector area of small circle = Pi x 1^2 / 6 = Pi / 6.
    Area triangle OAD = 1/2 x 1 x root 3 = 1/2 x root 3.
    Small yellow area subtended by angle OAD = area of triangle minus area of sector.
    Small yellow area = 1/2 x root 3 - Pi / 6.
    There are six of these small congruent yellow areas.
    Total yellow area = 3 root 3 - Pi.

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @phungpham1725
    @phungpham1725 6 месяцев назад +1

    Alternative solution:
    1/ R=2
    2/ The three arcsAB= AC=BC so the angle at the center of the 3 sectors = 120 degrees
    So by using the cosine law
    Side of the equilateral = sqR+sqR -2 RxR cos (120 degrees) = 4+4 -2 x2x2(-1/2)= 12
    side of the equilateral = 2 sqrt3.
    2/ The distance from O to one side= r= 1/2R=1
    3/ Area of the yelllow region = sq(2sqrt3).sqrt3/4 - pi=3sqrt3- pi=2.05 sq units

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @unknownidentity2846
    @unknownidentity2846 6 месяцев назад +2

    Let's find the area:
    .
    ..
    ...
    ....
    .....
    First of all we calculate the radius R of the circumscribed circle:
    A = πR²
    4π = πR²
    4 = R²
    ⇒ R = 2
    May s be the side length of the equilateral triangle. Then we can apply the relation between the area A of the triangle, its side length and the radius of the circumscribed circle:
    R = AB*AC*BC/(4*A(ABC)) = s*s*s/(4*(√3/4)*s²) = s/√3 ⇒ s = √3*R
    The radius r of the inscribed circle can be calculated from the triangles area A and perimeter P:
    r = 2*A(ABC)/P(ABC) = 2*(√3/4)*s²/(3*s) = s/(2√3)
    Now we are able to calculate the area of the yellow region:
    A(yellow)
    = A(triangle ABC) − A(inscribed circle)
    = (√3/4)*s² − πr²
    = (√3/4)*s² − π*(s/(2√3))²
    = (√3/4)*s² − π*s²/12
    = (√3/4 − π/12)*s²
    = (√3/4 − π/12)*3*R²
    = (√3/4 − π/12)*3*2²
    = 3√3 − π
    ≈ 2.055
    Best regards from Germany

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @santiagoarosam430
    @santiagoarosam430 6 месяцев назад +1

    Radio del círculo exterior =√4=2→ El centro de ambos círculos coincide con el baricentro del triángulo equilátero de lado b y altura h→ h=2+1=3→ b/2=√3→ Radio del círculo interior =r =h/3=1→ Área amarilla =(h*b/2)-πr² =3√3 -1*π → 3√3 -π.
    Gracias y saludos.

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @prossvay8744
    @prossvay8744 6 месяцев назад +3

    Connect O to A ; B and C
    So AOB=AOC=BOC=120°
    Big circle area=4π
    So R=2
    In triangle AOB
    Law of cosines
    AB^2=OA^2+OB^2-2(OA)(OB)cos(120°)
    AB^2=2^2+2^2-2(2)(2)cos(120°)
    So AB=2√3
    Area of triangle=1/2(2√3)^2sin(60)=3√3
    3√3=3(1/2(2√3)(r)
    So r=1
    Yellow area=3√3-π(1^2)=3√3-π square units=2.05 square units.❤❤❤❤

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @devondevon4366
    @devondevon4366 6 месяцев назад +1

    2.05615
    Draw a line inside the equilateral from the circle's center to B and another from its center to A, forming a 120-degree triangle
    Draw a line from the circle's center to B and one from the center to the point of tangency on line AB to form a 30-60-90
    right triangle, BOP.
    Since the radius of the large circle = 2 (given its area of 4 pi), then the radius of the small circle is 1 (since in 30-60-90
    right triangle the ratio is a , 2a, and a sqrt 3 ), and BP = sqrt 3 (since a =radius =1)
    Hence, length AB = 2 sqrt 3 since it is twice BP. Hence, the length of the equilateral triangle = 2 sqrt 3
    Hence, the area of the equilateral triangle =
    sqrt 3/4 * 2 sqrt 3 * 2 sqrt 3 = 5.19615
    The radius of the small circle = pi or 3.14 (since its radius =1 , see above)
    Hence, the area of the yellow region is 5.19615 - 3.14 = 2.05615

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @MrPaulc222
    @MrPaulc222 6 месяцев назад +1

    R=2
    Triangle comprises 6 30,60,90 triangles that have hypotenuses of 2.
    They each have short sides of 1 and sqrt(3).
    This gives the area of the equilateral as 3*sqrt(3) un^2.
    r is the shortest leg of one of those triangle, so r=1.
    Small circle area is pi un^2.
    Yellow area is 3*sqrt(3) - pi
    3*1.732 - 3.142 = 5.196 - 3.142
    2.054 un^2 (rounded).
    Now looked: okay our answers were 0.001 apart, which is due to rounding, so no problem.

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @phungpham1725
    @phungpham1725 6 месяцев назад +1

    1/ Let R, r and a be the radius of the big, small and side of the equilateral triangle.
    Extend AO intersecting AC at point H and the big circle at A’.
    We have AA’ is the perpendicular bisector of BC and the triangle BHO is a 30-90-6O special one.
    R= 2 -> OH=1 and BH=sqrt3
    So, BC= 2BH = a =2 sqrt3
    and r= OH= 1
    Area of the yellow region = Area of the equilateral - Area of the small circle
    = sq (2sqrt3).sqrt3/4 - pi
    = 3sqrt3- pi= 2.05 sq units😅

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @ryanmartinez7213
    @ryanmartinez7213 6 месяцев назад

    Non-geometry problems, PLZZZZZZZZ!

  • @juanalfaro7522
    @juanalfaro7522 5 месяцев назад

    4 π = π*R^2 -> R=2. Now COB angles are 30, 30, 120 and BC/sin 120 = 2/sin (30) --> BC=AB=AC=2*sqrt (3). Now [ABC} = [2*sqrt (3)] ^2 *sqrt (3)/4 = 12*sqrt (3)/4 = 3*sqrt (3)
    Semi-Perimeter = 3*2sqrt (3)/2 = 3*sqrt (3) = S. Now [ABC] = 3*sqrt (3) = S*r = 3*sqrt (3) * r --> r=1 unit (Thus A (small circle = π*1^2 = π)
    Yellow Area = [ABC] - π*r^2 = 3*sqrt (3) - π sq. units

  • @quigonkenny
    @quigonkenny 6 месяцев назад +1

    Outer circle O:
    Aᴏ = πR²
    4π = πR²
    R² = 4
    R = √4 = 2
    Draw OA, OB, and OC. As ∆ABC is equilateral, ∠AOC = ∠COB = ∠BOA = 360°/3 = 120°.
    Let M, N, and P be the points of tangency between inner circle O and AB, BC, and CA respectively. Draw OM, ON, and OP. As AB, BC, and CA are tangent to inner circle O, ∠AMO = ∠BNO = ∠CPO = 90°, so OM bisects AB, ON bisects BC, and OP bisects CA. As OM, ON, and OP are all radii of inner circle O and length r, and as ∆ABC is equilateral and thus AM = MB = BN = NC = CP = PA, and as OA, OB, and OC are all radii of outer circle O and length 2, then ∆AMO, ∆OMB, ∆BNO, ∆ONC, ∆CPO, and ∆OPA are all congruent triangles.
    As ∆ABC is equilateral and all 3 internal angles equal 60°, and as OA bisects ∠CAB by symmetry, then ∠PAO = ∠OAM = 30° and ∆AMO (and all congruent triangles) is a 30-60-90 special right triangle, OM (= ON = OP) = OAsin(30°) = 2(1/2) = r = 1, and AM (= MB = BN = NC = CP = PA) = OAcos(30°) = 2(√3/2) = √3.
    The yellow area is equal to the area of triangle ∆ABC minus the area of inner circle O.
    Yellow area:
    Aʏ = bh/2 - πr² = (BN+NC)(OA+ON)/2 - π(OM)²
    Aʏ = (√3+√3)(2+1)/2 - π(1)²
    Aʏ = 2√3(3)/2 - π = 3√3 - π ≈ 2.05 sq units

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @nandisaand5287
    @nandisaand5287 6 месяцев назад +1

    I didnt bother with trig, I just saw
    Height=r+R
    =(1)+(2)=3
    Therefore Area of Triangle:
    =½BH
    =½(2SQRT(3))•3
    =3SQRT(3)

    • @PreMath
      @PreMath  6 месяцев назад

      Thanks for the feedback ❤️

  • @giuseppemalaguti435
    @giuseppemalaguti435 6 месяцев назад +1

    R=2...l=2√3...r=1.. Ayellow=(1/2)(2√3)^2sin60-π(1)^2=3√3-π.

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @LuisdeBritoCamacho
    @LuisdeBritoCamacho 6 месяцев назад +1

    STEP-BY-STEP RESOLUTION PROPOSAL :
    01) Pi * R^2 = 4 * Pi ; R^2 = 4 ; R = +/- sqrt(4) ; R = +/- 2 ; R = 2
    02) OA = OB = OC = R = 2 lin un
    03) Inscribed Angles : Angle ABC = Angle BCA = Angle CAB = 120º
    04) Inner Angles : Angle AOB = Angle BOC = Angle COA = 60º
    05) Tangency Points between Equilateral Triangle and Small Circle : D ; E ; F
    06) OD = OE = OF = r lin un
    07) Now we have 3 Isosceles Triangles : [AOB] ; [BOC] ; [COA] subdivided in 6 Rigth Triangles (30º - 60º - 90º) : [AOD] ; [BOD] ; [BOE] ; [COE] ; [COF] ; [AOF]
    08) Let's call the Big Cathetus X and Small Cathetus Y.
    09) cos (30º) = X/2 ; X = 2 * cos (30º) ; X = 2 * (sqrt(3)/2) ; X = sqrt(3) lin un
    10) sin (30º) = Y/2 ; Y = 2 * sin (30º) ; Y = 2 * 1/2 ; Y = 1 lin un
    11)OD = OE = OF = r = 1 lin un
    12) Small Circle Area (A) = Pi sq un
    13) Blue Triangle Area with Sides equal to 2*sqrt(3) = 3*sqrt(3) ; BTA ~ 5,19615 sq un (Using Heron's Formula).
    14) Yellow Area = (BTA - SCA) sq un ; YA = [3*sqrt(3) - Pi] sq un ; Yellow Area ~ 2,055 sq un
    Thus,
    OUR BEST ANSWER IS :
    The Yellow Area is equal to approx. 2,055 Square Units. Exact Form : [(3*sqrt(3)) - Pi] Square Units.
    Best Wishes from Islam (Peace on Earth) - Al Andalus.

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!🌹
      Thanks for sharing ❤️🙏

  • @MaximeDube-wh2zr
    @MaximeDube-wh2zr 6 месяцев назад +1

    3r=h
    h=(√3/2)x
    r=(√3/6)x
    (x/2)^2 +((√3/6)x)^2 =4.... x=2√3
    .
    ..
    ...
    h=3
    r=1
    A=3√3-π

    • @PreMath
      @PreMath  6 месяцев назад +1

      Excellent!
      Thanks for sharing ❤️

  • @Nothingx303
    @Nothingx303 6 месяцев назад +3

    I solved it using my pink color muscles 💪 😏

    • @PreMath
      @PreMath  6 месяцев назад

      Bravo!
      Thanks for the feedback ❤️

  • @toninhorosa4849
    @toninhorosa4849 6 месяцев назад +1

    I solve a little different.
    Big circle area = 4π
    πR^2 = 4π
    R^2 = 4π/π
    R^2 = 4
    R = 2
    Equilateral blue triangle ABC have 3 equal sides and 3 equal angles = 60° each one.
    From point "O" we draw a perpendicular until we reach straight AB at point D. Forming a right angle at this point D. And we join point A until we reach straight BC where we mark point E. This straight AE passes through point "O " and will form ∆AOD which has a right angle at D. And angle A is 30° (1/2 of 60°).
    ∆AOD is right triangle
    Angle A = 30°
    Angle D = 90°
    Angle O = 30°
    AO = R = 2
    OD = (1/2)AO = (1/2)*2 = 1
    AD = √3
    BD = √3
    AB= AC = BC = 2√3
    Equilateral ∆ Area = 1/2*base*height
    Height = AE = AO+OE=R+r
    Height = 2+1 = 3
    ∆ABC area = (1/2)*2√3*3
    ∆ABC area = 3√3
    Small cicle area = πr^2 = 1π
    Yellow area = 3√3 - π
    = 2,054559769 unit.^2

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @devondevon4366
    @devondevon4366 6 месяцев назад +1

    2.056

    • @PreMath
      @PreMath  6 месяцев назад

      Excellent!
      Thanks for sharing ❤️

  • @AzalinKit
    @AzalinKit 6 месяцев назад

    bill cipher

  • @sergioaiex3966
    @sergioaiex3966 24 дня назад

    Solution:
    Yellow Area = Equilateral Triangle Area - Small Circle Area ... ¹
    Area of ​​Large Circle = 4π
    A = π R²
    4π = π R² (÷π)
    R² = 4
    R = 2
    Therefore, when connecting O to B, we have R = 2 and we form a 30°- 60° - 90° Special Triangle and, thus, r = 1 and AB = BC = AC = 2√3
    Area of ​​Small Circle = π r²
    Area of ​​Small Circle = π (1)²
    Area of ​​Small Circle = π
    Area of ​​Equilateral Triangle = ½ AB . r + ½ BC . r + ½ AC . r
    Area of ​​Equilateral Triangle = ½ 2√3 . 1 + ½ 2√3 . 1 + ½ 2√3 . 1
    Area of ​​an Equilateral Triangle = √3 + √3 + √3
    Area of ​​an Equilateral Triangle = 3√3
    Substituting in ¹
    Yellow Area = 3√3 - π Area Units ✅
    Yellow Area ≈ 2.0545 Area Units ✅

  • @ОльгаСоломашенко-ь6ы
    @ОльгаСоломашенко-ь6ы 6 месяцев назад +2

    R=2, R=a/√3, r=a/(2√3)= R√3/(2√3)=1.

  • @ยี่สิบเก้าพฤศจิกา

    R=2=c ; a=1=r ; b=/3 ; base=/3+/3=2/3 ; high=R+r=2+1=3

  • @CliffordMorris-ls9lc
    @CliffordMorris-ls9lc Месяц назад

    You have certainly stirred the mathematical pot so even if your podcasts do nothing else they cause an awful lot of Mathematics to be done.

  • @CliffordMorris-ls9lc
    @CliffordMorris-ls9lc Месяц назад

    Stretching out a basic idea is silly. The maths should be outlined in your plan . People doing maths do not need this laborious step by step as they need guidance not be treated as totally incapable of following your method. 10:53

  • @wackojacko3962
    @wackojacko3962 6 месяцев назад

    Tips and Tricks...clickbait for those needing too acquire Algebra and Geometry skills i.e area of circle formula, Perpendicular Bisector Theorem, Area of the Triangle Formula, Circle Theorem, Equalateral Triangle...I know a lot of Tricks cuz I am a magician and can pull a rabbit out of a hat and make things disappear. 🙂

    • @PreMath
      @PreMath  6 месяцев назад +1

      😀😀😀