The RADII of the top and bottom of a frustum of a cone are 3cm and
7.5cm respectively. If the height of the frustum is 30cm, calculate (i) the
curved surface area (ii) the volume of the frustum.
Note: Show the workings
How high would it be if you had not cut the top off?
well 30/ (7.5 -3) = h/7.5
h = 30 * 7.5 /4.5 = 50 on the nose
so calculate the volume and side area of a cone with bottom radius 7.5 and height 50
from that subtract
the volume and side area of a cone of height 20 and bottom radius 3