Question

Two poles of height 6 m and 11 m stand vertically upright on a plane ground. If the distance between their feet is 12 m then the distance between their tops is ______.

Options

• 12 m

• 13 m

• 14 m

• 15 m

Answer 1

Two poles of height 6 m and 11 m stand vertically upright on a plane ground. If the distance between their feet is 12 m then the distance between their tops is 13 m.

Explanation:

Let the poles be AB = 6 m and CD = 11 m with feet A and C 12 m apart.

Draw BE || AC so CE = AB = 6 m and BE = AC = 12 m.

Then DE = CD – CE

= 11 – 6

= 5 m

In right triangle BED,

`BD = sqrt(BE^2 + DE^2)`

= `sqrt(12^2 + 5^2)`

= `sqrt(169)`

= 13 m