Let's choose 43° to be our angle. We know the opposite, and want to know the hypotenuse. Sine is the trig. we use for opposite over hypotenuse. sinθ = opposite/hypotenuse sin(43)=27/x We want to isolate <em>x</em>, so that looks like: x = 27/sin(43) Therefore, the value of x is 27/0.682 or ≈39.589 or F