Question

The surface area of a right cone is 400.2 m2. The radius of the cone is 6.0 m. Determine the height of the cone to the nearest metre.

Answer 1

S = πr(r + √(h² + r²))
400.2 = 3.14(6)(6 + √(h² + 6²))
400.2 = 18.84(6 + √(h² + 36))
18.84 18.84
21¹⁰⁹/₄₇₁ = 6 + √(h² + 36))
- 6 - 6
15¹⁰⁹/₄₇₁ = √(h² + 36)
231²²¹⁰⁰⁵/₂₂₁₈₄₁ = h² + 36
- 36 - 36
195²²¹⁰⁰⁵/₂₂₁₈₄₁ = h²
14 ≈ h