A circular sector with a radius of $25$ and a central angle of $345.6^\circ$ is rolled to form a cone. Find the volume of the cone.
Please help!
The radius will form the "slant height" of the cone
The arc length of the sector will form the circumference of the cone
This is 2*pi (25) (345.6 / 360) = 48pi units
The radius of the cone can be found as
Circumference = 2pi * r
48 pi = 2pi * r
48 = 2r
r = 24
The height of the cone = sqrt [ slant height^2 - radius^2 ] =
sqrt [ 25^2 - 24^2 ] =
sqrt [625 - 576] = sqrt [49] = 7
Volume (cone) = (1/3) pi * r^2 * height = (1/3)pi ( 24)^2 ( 7) = 1344 pi units^3