The main trunk of a tree is in the shape of a cylinder. The distance around its cross-section is 47.1 cm and its height is 0.7 m.
a) What is the radius of the cross-section?
b) What volume of wood is there in the trunk? Show your work.
(a) The distance around the cross-section is the circumference of a circle and we can find the radius thusly:
47.1 = 2 pi * r
47.1 / (2pi) = r ( in cm )
(b) Volume of a cylinder =
pi * r^2 * height =
[ Note that .7 m = 70cm]
pi [ 47.1 / (2pi) ] ^2 * 70 ≈ 12357.5 cm ^3