Question

If the point P(-4/5,y) lies on the unit circle and P is in the third quadrant, what does y equal? If necessary, use the slash mark ( / ) for a fraction bar.

Answer 1

-3/5

Explanation:

Answer 2

We use the fact that x2+y2=1 This is the equation of the unit circle.
We know that x=-4/5, so plug this in and solve for y
x2+y2=1 (−4/5)^2+y2=1 16/25+y2=1 y2=1−16/25 y2=9/25 y=−square root of 9/ 25
y = -3/5