By your very own "not true to the scale", you cannot assume that the tops of those two indents are in line. That alignment must be explicitly stated, which it is not.
@@theoyanto The side opposite 8 can be longer than 8, or shorter than 8. The other unknown would then stretch or shrink accordingly., leaving the tops of those indents NOT in line. Alternatively you come to the same conclusion by varying the far left vertical. There is, of course, the other oop, that being the two supposedly right angles, but they are not marked. That, however does not change my argument.
@@johankotze42 oh yeah, I get that now, so that would also affect the length 5 and therefore change the circumference , thanks for clarifying that Johan
@@theoyanto No, it will not change 5. The 5-line is fixed at 5 in length, starting at the bottom of the 9-line. The 5-line's top will remain 4 below the 19-line. But the 8-line and the 3-line will move up or down in unison.
From my perspective there is a problem here. There is a side that is 8 units long, but nothing says that the opposite side has the same length. Hence considering that both side have equal length is only an assumption and not mathematically rigorous.
@@theoyanto That changes nothing. There is nothing stating that either the 8 length line is equal in size to the line on its right or that a single line passes through the two inner bottom lines. Such information should not be assumed as given no matter what it appears. The right angles do not determine more than the far left line is one shorter than the line to the right of the 8 line.
@@RoderickEtheria oh yeah, I get that now, so that would also affect the length 5 and therefore change the circumference , thanks for clarifying that 👍🏻
@@theoyanto And, actually, it's worse than that because there are two undefined angles that only need to add up to 180, and don't need to be 90 degrees each. A 37-143 split on those angles would radically change the value of the perimeter.
You are correct. First thing I noticed. There is simply not enough info in the diagram to ensure that they form a horizontal line. Imagine that you nudge the right hand one up just a tiny bit so each segment no longer forms 1 single straight line. Sorry to be so picky, but it is what it is - not enough info.
There need to have a BIG assume of the two horizontical sections connect vertical segment with 3 unts and the vertical segment with 5 units are in the same horizontal level. Otherwise the calculation didn't work.
And a big assumption that the two unmarked angles must be 90 degrees each, rather than simply totalling to 180. Even if the length of the line opposite the 8 is equal to 8, as the angle at the bottom of the 5 line approaches 180, the perimeter approaches infinity.
See comments below. Nice try Premath but your going to have to come clean on this one. There is not enough info to ensure that the side opposite the 8 is actually 8. Don't feel too bad though. Everyone is allowed to make a small slip from time to time. We all have. Keep up the good work.
To chime in with the other comments down below. First, there are no right-angle indicators for the interior angle below the "3", and no right-angle indicator for the angle below and to the right of "5", which means we cannot assume they are right angles, since there are two of them which are independent. Further into this is that no indication is given that the "horizontal" segments which are assumed to be in-line with one another are co-linear. (One could prove they were parallel, though). Love your videos and the neat problems, and I hope you take these comments to be constructive criticism. Keep up the good work. I would also like to point out the *value* of this mistake being shared, which is for me personally, to question my assumptions, before and during the analysis of the problem.
If you lay out the figure in CAD, you can stretch the figure through the two unknown verticals without changing any of the given dimensions, thus changing the overall perimeter. There are infinite solutions here.
I was having my mom work this problem and noticed that there is an assumption that the 2 short horizontal lines are at the same height. There isn't anything that says this, unless I am missing something. On the right side we come down 9, then up 5. It seems like an assumption that we then come down 8 but that would easily be that we come down 9. Then up 8 and then back down what would be another 8. That would make the perimeter 2 inches longer than the solution. Am I missing something about assuming those two horizontal lines are at the same height?
This was not a good video because the answer is assuredly wrong. The uncensored heights are taken one from the left of the shape and one from the right of the shape, and there is no reason to assume scale. As such, you cannot determine the perimeter of this shape.
Unfortunately, this problem is based on two huge assumptions. 1)The line to the right of the line labeled 8 is of the same length as the line labeled 8. 2)The two angles without known values are both 90 degrees rather than simply summing to 180. If either of these two assumptions is incorrect, you cannot determine the value of the perimeter, and, as this drawing is not to scale, we cannot simply make assumptions that these are true. As such, the answer to this problem is that we do not have enough information, not the answer which is provided in this video.
This puzzle is a disaster and a half. Two angles are unknown, which the only thing we can say about then is they sum to 180. The shift of those angles could create disastrous ramifications on the size of the perimeter. Also, the two unmeasured legs assumed to be vertical are on opposite sides of the shape, and these lines can be shifted quite wildly even if the angles are all 90 degrees. Without the puzzle being drawn to scale, you should not assume the line directly to the right of the line marked 8 has an equal height of 8, unless clearly defined as such. The only thing you could tell about the two unmarked vertical lines, if the angles were all 90 degrees, is that the inner one is 1 greater than the outer one. As it stands, both conundrums would break the puzzle by themselves, but both together make this puzzle absolutely irredeemable.
He made it too long. The only vertical side needed was the farthest left which is (9-5)+3=7. 9-5 comes from the two farthest vertical sides on the right.
Nice question and elegant explanation. Thank you for the effort and time spent sir.
You are very welcome!
So nice of you.
Thanks for your continued love and support!
You are awesome. Keep it up 👍
Love and prayers from the USA! 😀
By your very own "not true to the scale", you cannot assume that the tops of those two indents are in line. That alignment must be explicitly stated, which it is not.
What else could they be?
@@theoyanto The side opposite 8 can be longer than 8, or shorter than 8. The other unknown would then stretch or shrink accordingly., leaving the tops of those indents NOT in line. Alternatively you come to the same conclusion by varying the far left vertical. There is, of course, the other oop, that being the two supposedly right angles, but they are not marked. That, however does not change my argument.
@@johankotze42 oh yeah, I get that now, so that would also affect the length 5 and therefore change the circumference , thanks for clarifying that Johan
@@theoyanto No, it will not change 5. The 5-line is fixed at 5 in length, starting at the bottom of the 9-line. The 5-line's top will remain 4 below the 19-line. But the 8-line and the 3-line will move up or down in unison.
We can't find the answer... 78 it is possible to answer but not exactly the answer... not enough information to find the answer 😢
From my perspective there is a problem here. There is a side that is 8 units long, but nothing says that the opposite side has the same length. Hence considering that both side have equal length is only an assumption and not mathematically rigorous.
All the corners are right angles
@@theoyanto That changes nothing. There is nothing stating that either the 8 length line is equal in size to the line on its right or that a single line passes through the two inner bottom lines. Such information should not be assumed as given no matter what it appears. The right angles do not determine more than the far left line is one shorter than the line to the right of the 8 line.
@@RoderickEtheria oh yeah, I get that now, so that would also affect the length 5 and therefore change the circumference , thanks for clarifying that 👍🏻
@@theoyanto And, actually, it's worse than that because there are two undefined angles that only need to add up to 180, and don't need to be 90 degrees each. A 37-143 split on those angles would radically change the value of the perimeter.
You are correct. First thing I noticed. There is simply not enough info in the diagram to ensure that they form a horizontal line. Imagine that you nudge the right hand one up just a tiny bit so each segment no longer forms 1 single straight line. Sorry to be so picky, but it is what it is - not enough info.
There need to have a BIG assume of the two horizontical sections connect vertical segment with 3 unts and the vertical segment with 5 units are in the same horizontal level. Otherwise the calculation didn't work.
And a big assumption that the two unmarked angles must be 90 degrees each, rather than simply totalling to 180. Even if the length of the line opposite the 8 is equal to 8, as the angle at the bottom of the 5 line approaches 180, the perimeter approaches infinity.
See comments below. Nice try Premath but your going to have to come clean on this one. There is not enough info to ensure that the side opposite the 8 is actually 8. Don't feel too bad though. Everyone is allowed to make a small slip from time to time. We all have. Keep up the good work.
The question does not indicate that the top horizontal levels of the 3 and 5 verticals are level.
That was my problem also. If they are, 9-5 to give 4, which means the left is 7 (4+3) way easier than the way he went about it.
To chime in with the other comments down below. First, there are no right-angle indicators for the interior angle below the "3", and no right-angle indicator for the angle below and to the right of "5", which means we cannot assume they are right angles, since there are two of them which are independent. Further into this is that no indication is given that the "horizontal" segments which are assumed to be in-line with one another are co-linear. (One could prove they were parallel, though). Love your videos and the neat problems, and I hope you take these comments to be constructive criticism. Keep up the good work.
I would also like to point out the *value* of this mistake being shared, which is for me personally, to question my assumptions, before and during the analysis of the problem.
If you lay out the figure in CAD, you can stretch the figure through the two unknown verticals without changing any of the given dimensions, thus changing the overall perimeter. There are infinite solutions here.
Worse yet, two of the angles are undefined.
@@RoderickEtheria Right! You can rotate the bottom section between the two undefined angles.
Very nice
Thanks Sir
I was having my mom work this problem and noticed that there is an assumption that the 2 short horizontal lines are at the same height. There isn't anything that says this, unless I am missing something. On the right side we come down 9, then up 5. It seems like an assumption that we then come down 8 but that would easily be that we come down 9. Then up 8 and then back down what would be another 8. That would make the perimeter 2 inches longer than the solution. Am I missing something about assuming those two horizontal lines are at the same height?
Hold on: You made a _masive_ assumption at 2:40
Split the 8 vertical to both sides to make 19 x 12 rectangle. Perimeter = 2*(19 + 12 + 3 + 5) = 78
Good..
19x2+9+5+8x2+3+(9-5+3)=38+9+5+16+3+7=78, done.🙂
Excellent!
Thanks for sharing! Cheers!
You are awesome. Keep it up 👍
Love and prayers from the USA! 😀
Wrong answer. Puzzle is broken. Refer to other comments in section.
Amazing 👍
Thanks for sharing😊😊
I have solved this by same way.. thank you sir this was a good video...
Excellent!
Thanks for sharing! Cheers!
You are awesome. Keep it up 👍
Love and prayers from the USA! 😀
This was not a good video because the answer is assuredly wrong. The uncensored heights are taken one from the left of the shape and one from the right of the shape, and there is no reason to assume scale. As such, you cannot determine the perimeter of this shape.
For adding in my head I got 72 so I have no idea how but I got close enough so I'm happy
Correct answer is hugely different. Correct answer is the puzzle is broken in two ways, and could give an infinite number of perimeters.
I don't know what I'm missing but I keep getting 7 for the left side
After finally using a calculator I got 78
Nice question
Good
Horizontal lengths =19x2=38
Vertical lengths = 9+5+8+8+3+7=40
Ans =78
Thanks for sharing! Cheers!
You are awesome. Keep it up 👍
Love and prayers from the USA! 😀
Unfortunately, this problem is based on two huge assumptions.
1)The line to the right of the line labeled 8 is of the same length as the line labeled 8.
2)The two angles without known values are both 90 degrees rather than simply summing to 180.
If either of these two assumptions is incorrect, you cannot determine the value of the perimeter, and, as this drawing is not to scale, we cannot simply make assumptions that these are true. As such, the answer to this problem is that we do not have enough information, not the answer which is provided in this video.
(2×19)+2(9+3+8)=78
Gracias y saludos.
Excellent!
Thanks for sharing! Cheers!
You are awesome. Keep it up 👍
Love and prayers from the USA! 😀
Excellent 30 second challenge
It seems some commentors are perhaps overthinking this mental arithmetic problem.
Thanks for your feedback! Cheers!
You are awesome, Ian. Keep it up 👍
Love and prayers from the USA! 😀
Yay! I solved it.
Thanks for video.Good luck sir!!!!!!!!!!!
78
L’énoncé ne précise pas que deux segments sont à la même hauteur
Length = 19, width = 9+8-5=12
Parameter without the 2 inward indentation is 2×(19+12) =62. Now add 2x3 + 2×5 = 16 inward incursions. Total = 62+16=78. Done.
This puzzle is a disaster and a half. Two angles are unknown, which the only thing we can say about then is they sum to 180. The shift of those angles could create disastrous ramifications on the size of the perimeter.
Also, the two unmeasured legs assumed to be vertical are on opposite sides of the shape, and these lines can be shifted quite wildly even if the angles are all 90 degrees. Without the puzzle being drawn to scale, you should not assume the line directly to the right of the line marked 8 has an equal height of 8, unless clearly defined as such. The only thing you could tell about the two unmarked vertical lines, if the angles were all 90 degrees, is that the inner one is 1 greater than the outer one.
As it stands, both conundrums would break the puzzle by themselves, but both together make this puzzle absolutely irredeemable.
He made it too long. The only vertical side needed was the farthest left which is (9-5)+3=7. 9-5 comes from the two farthest vertical sides on the right.
la dernière verticale =9-5+8-8+3 =7
❤🥂😎