Question

A person standing on the bank of a river observes that the angle of elevation of the top of a tree standing on the opposite bank is 60 degree. When he moves 40 metres away from the bank, he finds the angle of elevation to be 30 degree. Find out the height of the tree and the width of the river.

Answer 1

height of the tree is=h. the width of the river=d. ABC. tan60=opposite/adjacent. tan60=AC/BC. =root 3 = Ac/60. =AC=60root3_equationnumber 3. PQR. =tan30= PQ/PR=1/root3=PQ/30= PQ=30root3 _equation number 2 from equation no 1&2. H=45