The picture shows a barn door:
A barn door has two parallel bars. A support AB runs across the diagonal between the two parallel bars. The angle made by the diagonal with the parallel bar on top is 60 degrees. The distance between the two parallel bars is 9 feet.
What is the length of the support AB?
9 divided by tan 60 degrees
9 sin 60°
9 cos 60°
9 divided by sin 60 degrees