a tower and a monumement stand on a level plane. The angles of depression of the top and bottom of monument as viewed from the top of the tower are 13 degree and 31 degree respectively. If the height of the tower is 145 ft.,find the height of the monument

Answer 1

Did you make a diagram?
You can find every possible angle in both triangles, one is right angled.
Start with the right-angled triangle and find its hypotenuse.
Then use the Sine Law in the next triangle.

Answer 2

45ft