What is the sine value for an angle of π/4 on the unit circle?
+
Math Question: What is the value of y when x = 3 in the circle function x^2 + y^2 = 25?
+
Math question: In a circle, if an angle at the center is twice the size of an angle at the circumference, and the angle at the circumference measures 60 degrees, what is the measure of the angle at the center?