Answer: 4.7
Explanation:
We are trying to find the opposite side from the angle and are given the adjacent side to the angle, so looking at SohCahToa we have (a) and need (o) so we would use tangent (tan)
tan(20) = o/a
tan(20) = x / 13, multiply 13 on both sides
13 * tan(20) = x
4.73161 = x, round to the nearest tenth and that is x = 4.7