The sine function is to find the ratio of the length of the leg opposite to the angle with the measure of value over the length of the hypotenuse of a triangle. The formulas for sine, cosine, and tangent can be memorized with the phrase SOH - CAH - TOA. (sine = opposite/hypotenuse, cosine = adjacent/hypotenuse, tangent = opposite/adjacent) Note that the result of the sine function will vary with the angle mode: when the calculator is set in Degree mode the sine function will have a different result than when the calculator is set in Radian mode.