FOUNDATIONS FOR SUCCESS: CONSULTATION DRAFT
Sketching and labeling the cross section makes clear the dimensions of each volume.
r h
h
h
r
r
r
r
The volume of each figure is calculated from the area of the base A and the height h.
1 Ah 3
In each case A p r2 and h p 2r.
1 r2 x 2r 3
2 2x 3 r 2r
Simplification yields:
2 3 3 r
4 r3 3
6 3 3 r
To find the ratios, divide by the common 1 factor of 3 r3.
2
4
6
Thus the ratios of the volumes are 1 : 2 : 3.
104 | Achieve, Inc.
2 Ah 3
Ah
r2 x 2r