The radius of the base of a conical tent is 9 m and its height is 12 m, find the cost of the material needed to make it if it costs ₹100 per π m².

Question

Question

This question was previously asked in

RRB NTPC CBT 2 Level -6 Official paper (Held On: 9 May 2022 Shift 1)

Answer 1

Given:

The radius of the base of a conical tent is 9 m and its height is 12 m

Concept used:

Curved surface area of a cone = π × Radius × Slant Height

Slant height = \(\sqrt{Radius^2 + Height^2}\)

Calculation:

Slant height of the conical tent = \(\sqrt{12^2 + 9^2}\) = 15 cm

Hence, the curved surface area of the conical tent = π × 9 × 15 = 135π m²

Thus, the cost of the material = (135π × 100) ÷ π = Rs. 13,500

∴ The cost of the material is Rs. 13,500.