In a right triangle, use the formula: sine = opposite side ÷ hypotenuse
Identify the angle you want to find sine for
Find the side opposite that angle
Find the hypotenuse
Divide the opposite side by the hypotenuse
Use a calculator for decimal results if needed
For special angles, use exact values:
sin(0°) = 0
sin(30°) = 1/2
sin(45°) = √2/2
sin(60°) = √3/2
sin(90°) = 1