find sine or cosine when given sine sin or cosine cos and quadrant of the angle

In this example, we are told the value for sine or cosine and the quadrant where the angle is located. We then use the pythagorean theorem to plug in the value that we know and solve for the other function by creating a power equation. We then check if the function should be positive or negative in the given quadrant by using "all students take calculus". Each part of this process is explained and written out step-by-step.