Question

A surveyor measured the angle of elevation of a flat spire as 15 degree from a point in horizontal group.He movrs 30m nearer to the flat and measure the angle of elevation at 43 degrees.Calculate the height of the spire to the nearest hundredth.

Answer 1

11.28m

Explanation:

The computation of the height of the spire is shown below:

let us assume the height of the spire be x

Now

For triangle ABD

Tan 43 degrees = h ÷ x

x = h × cot 43 degrees

= 1.07236 h

For triangle ABC

tan 15 degrees = h ÷ (30 + x)

0.2679 = h ÷ 30 + 1.07236h

8.038 + 0.28728 h = h

h = 11.28m