Question

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

Answer 1

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

y = - sqrt (16/25)

Answer 2

then the given pair must satisfy x^2 +y^2 = 1