Posted by Mary on .
The volume of a cone is 54 pi cubic inches. The radius and height of the cone are both reduced by a factor of 3 to create a new cone. What is the volume of the new cone?
Is the volume of the new cone 18pi cu in
A. 2 pi cu inches
B. 6 pi cu inches
C. 9 pi cu inches
D. 18 pi cu inches

geometry 
Mary  Help plz,
Is the answer 18 pi cu inches

geometry 
Henry,
V = (pi*r^2*h) / 3 = 54pi.
Vn = (pi*(r/3)^2*(h/3)) / 3 = 54pi,
Vn = (pi*(r^2/9)*(h/3)) / 3 = 54pi,
Vn = (pi*r^2*(1/27)*h) / 3 = 54pi,
We have divided the left side of our Eq by 27. Therefore , we must divide
the rt. side by 27 also:
Vn = (pi*r^2*(1/27)*h) / 3 = 2pi. =
New volume = "A".