Question #787a4

2 Answers
Jan 8, 2016

I have given an outline of the method you could use to solve each part of the question, and the answer I got at the end.

Explanation:

For part a:

As the volume of the two shapes is equal, we can equate those volume equations.
The ratio of the cone's height to its radius is h/rhr, so this is what you want to solve for.

I got h/r=12hr=12.

For part b:

Draw a pair of cylinders, and label them with the dimensions in terms of the small cylinder's radius.

The sum of the volumes is given to us, so we can form an equation in terms of the radius, and solve it for the radius, allowing us to give each cylinder's dimensions.

I got r=3/88r=388

Jan 9, 2016

h/r = 4/1hr=41, which means that hh is 4 times the rr
h:rh:r
4:14:1

Explanation:

The volume of sphere is given by the formula V_s= 4/3pir^3Vs=43πr3;
Thevolume of cone is given by the formula V_c=h/3pir^2Vc=h3πr2.

The condition here is that VV and rr of both figures are equal. By equating the two formulas, the following can be derived:

V_s=V_cVs=Vc
4/3pir^343πr3=h/3pir^2h3πr2
where r_s=r_crs=rc
4/cancel3cancel(pi)r=h/cancel3cancel(pi)
4r=h
h/r=4/1
h:r
4:1