# Height of a problem

**Geometry**Level 3

During a surveying work in a hilly area the top of a stack was sighted from two instruments A and B and angles of elevation were found to be 45(degree) and 53(degree) respectively. Instruments A and B are mounted on stand of height 1m and are placed at a horizontal distance of 100m.Angle of elevation of foot of stand at B from A is 37(degree). Assuming instruments, stands, stacks all in same vertical plane, the level difference between top of stack and instrument B is (take tan37(degree)=3/4)