Question

A circular ground of radius 50 m has to be covered with water proof sheet. The same amount of water proof sheet is also used for making conical tents. If the base area of tent is 625 $m^2$then the height of tent is____${cm}^2$

• A. 90.42
• B. 96.8
• C. 100.6
• D. 88.5

Answer 1

The correct option is B

96.8

Surface area of water proof sheet = Curved surface area of conical tents

$\pi$ ${r_1}^2$ = 625$\pi$

${r_1}^2$ = 625

$r_1$ = 25m

Now in the $1^{st}$ equation

${50}^2$ = 25 x l => l = 100 m

We know that Slant height = $\sqrt[2]{2\left(h^2\right)+\left(r^2\right)}$ = $\sqrt[2]{2\left(h^2\right)+\left({25}^2\right)}$ =100

$h^2$ = $\sqrt{{100}^2-{25}^2}$

h = $\sqrt[2]{29375}$ = 96.82