Answer:
45.074
Step-by-step explanation:
You can use the trigonometric function sin which is equal to opposite/hypotenuse. Since you are given the angle and the hypotenuse you can use that to solve for the value of BC
[tex]sin(\theta) = \frac{opposite}{hypotenuse}\\\\sin(51) = \frac{BC}{58}\\sin(51) * 58 = BC\\0.7771 * 58 = BC\\45.074 \approx BC[/tex]
