The hypotenuse is sqrt ( (-9)^2 + 10^2) = sqrt(181)
Sin(theta) = the y value of the point/hypotenuse
The y value = 10
Sin(theta) = 10/sqrt(181) Normally your should rationalize the denominator.
Sin(theta) = 10 * sqrt(181) / (sin(181)*sin(181)) = 10 * sqrt(181) / 181
The answer is A <<<<