If cos 0 = - 4/9 with 0 in Quadrant II, find sin 0

Sin0 = y/r

X = - 4 and r = 9 (radius is also the hypotenuse)

In quadrant II y is positive

X^2 + y^2 = r^2

-4^2 + y^2 = 9^2

16 + y^2 = 81

Y^2 = 81-16

Y^2 = 65

Y = sqrt65

Sin0 = sqrt65/9