Saxon Algebra 2 , Lesson #44, #19

[Marilyn]

Is there an error with this problem?

[Karri]

You are asked to find the volume of the cone that is 4 ft. high. Dimensions of the base are given in inches.



First you need to find the area of the base (figure drawn in the book). Separate this figure into three figures and find the area of each as follows:a half circle w/radius of 4(Pi times the radius squared) divided by 2 or(3.14 times 16) divided by 2 or 25.12


a trianglebase equals 2 + 4 + 6 or 12height equals 8

1/2 bh = 1/2(12)(8) or 48

a half circle w/radius of 2 (notched area)(Pi times the radius squared) divided by 2 or(3.14 times 4) divided by 2 or 6.28Now take add the area of the half circle w/radius of 4 and the area of the triangle, then subtract the notched area.


25.12 + 48 - 6.28 = 66.84 (area of base)

To find the volume of the cone:

1/3bh

1/3 (66.84)(48) = 1069.44 cubic inches.