A point P is often identified in mathematics using the notation P ( x , y ) to reference a point at coordinates ( x , y ) . If P ( x , 8 9 ) is on the unit circle in quadrant II, then x =

Question

X=?

Answer 1

The formatting on your question didn't come out right but I'll assume you meant to say that the point is:

P(x, 8/9)

Here is a sketch:

Use the Pythagorean Theorem:

x² + (8/9)² = 1²

x² = 1 - 64/81

x² = 17/81

x = √17/9 but since this is in Q2, x = -√17/9