Question

a guy wire is 13.5 m long. it supports a vertical pole. the wire is fastened to the ground 9.5 m from the base of an 8.7 m tall pole. calculate the measure of the guy wire and the ground.

Answer 1

If the ground slopes downwards from the base of the post to the guy wire ground attachment, we use the Cosine Rule to find the angle between the guy wire and the sloping ground:

8.7²=13.5²+9.5²-2(13.5)(9.5)cosα where α is the required angle.

cosα=(13.5²+9.5²-8.7²)/256.5=0.7673 approx, making α=39.89° approx.