Question

a cone has circular base of radius 5cm and a hieght of 12cm. find the curved surface area

Answer 1

If radius = 5 and height = 12 then (using the Pythagorean Theorem) the slant height = square root (12^2+ 5^2) =
square root (169) = 13
The formula for the lateral area (curved surface area) can be found here:
http://www.1728.org/volcone.htm
Lateral Area = (PI * r * slant height)
Lateral Area = 3.14159 * radius * 13
Lateral Area = 3.14159 * 5 * 13
Lateral Area = 204.20