sin α = opposite leg/ hypotenuse
Terminal side forms a hypotenuse of a triangle.
x- coordinate gives adjacent leg,
y-coordinate gives opposite leg. (-8)
Hypotenuse ² = (leg1)² +(leg2)²
Hypotenuse ² = 15² +(-8)² = 289
Hypotenuse =√289 = 17
sin α = - 8/17
