Answer:
x ≈ 34.9
Step-by-step explanation:
x is the hypotenuse of the triangle, for which one leg is given. Either the sine or the cosine relation can be used. We choose to use the cosine relation:
Cos = Adjacent/Hypotenuse
cos(53°) = 21/x
x = 21/cos(53°) ≈ 34.9
