Identify the angle
Choose the correct right triangle or unit circle value
Use the formula: sin(θ) = opposite / hypotenuse
Measure the opposite side to the angle
Measure the hypotenuse
Divide opposite by hypotenuse
If using a calculator, enter the angle in the correct mode: degrees or radians
Press the sine function: sin(θ)
Read the result
For special angles, use exact values if known
Simplify the result if possible