Question

If the point P( -3/5,v) lies on the unit circle and P is in the third quadrant, what does y equal?

Answer 1

y = -4/5

Explanation:

Both coordinates are negative in the 3rd quadrant. The value of y is the other leg of the right triangle with hypotenuse 1. The Pythagorean theorem is helpful.

y = -√(1 -(-3/5)^2) = -√(1 -9/25) = -√(16/25)

y = -4/5