14 - Reference Angles Explained - Sine, Cosine & Unit Circle - Part 1

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In this lesson, you will learn what a reference angle is and why they are important in trigonometry, precalculus, and calculus. A reference angle is the angle measure from the terminal ray of the angle to the x-axis. It is always a positive angle. The reason we use reference angles is because the sine and cosine (sin & cos) of any angle around the unit circle can be found by examining the corresponding reference angle. In other words, the sine and cosine ratios are the same values all around the unit circle, and the magnitude of this value only depends on the reference angle. We then apply the correct sign to the final answer depending on what quadrant the original angle is located. In this lesson, we will draw an angle, find the reference angle, and discuss how to find the sine and cosine of the angle using its corresponding reference angle.

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I was paying attention while watching your lesson on the unit circle. You hinted to the reference angle to the X axis. Here I'm only learning the word prime.
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[@denvercharlebois699]

What if the reference angles aren't special triangles like 30, 60 and 45? How would I go about finding the values of the sine and cosine? Anytime I input it I get a crazy decimal number how do I go about finding it in fraction form?

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I think trigonometric values remain the same either we move clockwise or anticlockwise observing the quadrant rule of signs.
We have two trig. identities Ie sin(-β)
.=-sinβ
cos(-β)=cosβ Is β is an acute angle?
Practice is not necessarily doing the same thing repeatedly rather it is seedling and cultivating some good habits.

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Could this be used to measure volts or currents or ohms ?

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Is a 315° a 1.75 I divided that by 180°

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4:56 the reference angle can't be 90

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