A circus tent is made of canvas and is in the form of right circular cylinder and a right circular cone above it. The diameter and height of cylindrical part of tent are 126 m and 5 m respectively. The total height of the tent is 21 m. Find the total cost of tent if canvas used costs ₹36 per square metre.

The below figure shows the circus tent:

Diameter of cylindrical part = 126 m.

Radius of cone = Radius of cylinder = r = $\dfrac{126}{2}$ = 63 m.

Height of cylindrical part (h₁) = 5 m,

Total height of tent = 21 m,

Height of conical part (h) = 21 - 5 = 16 m.

Slant height of cone (l) = $\sqrt{r^2 + h^2}$

$= \sqrt{63^2 + 16^2} \\[1em] = \sqrt{3969 + 256} \\[1em] = \sqrt{4225} \\[1em] = 65 \text{ m}.$

Surface area of tent (S) = Surface area of cylinder + Surface area of cone.

$S = 2πrh$1 + πrl \\[1em] = πr(2h1 + l) \\[1em] = \dfrac{22}{7} \times 63 \times (2 \times 5 + 65) \\[1em] = 22 \times 9 \times (10 + 65) \\[1em] = 198 \times 75 \\[1em] = 14850 \text{ m}^2.

Cost of one 1 m² cloth = ₹ 36.

Total cost = 14850 × 36 = ₹ 534600.

Hence, the total cost of tent is ₹ 534600.