Find the length (in feet) of the slant height ℓ of a right circular cone with r = 8.4 ft and h = 3.5 ft. Use the fact that r2 + h2 = ℓ2 in a right circular cone.

Question

Find the length (in feet) of the slant height ℓ of a right circular cone with r = 8.4 ft and h = 3.5 ft. Use the fact that r² + h² = ℓ² in a right circular cone.

( I thought the answer was 1295.56? I also thought I was just supposed to plug the numbers in.)

Answer 1

If r² + h² = ℓ²

then ^√(r² + h^{2) =} ℓ

Therefore √(8.4² +3.5²) = ℓ = 9.1