The height of the smaller can would need to be 12.8 cm.
First find the volume of the larger can of paint. The volume of a cylinder is given by the formula V=πr²h
Using the dimensions of the larger can, we have V = 3.14(8²)(20) = 4019.2
Since he has 1/4 of this can, divide the volume by 4: 4019.2/4 = 1004.8
We will use this as the volume of the smaller can. Substituting this in along with the radius of the smaller can (using the same volume formula), we have: 1004.8 = 3.14(5²)h 1004.8 = 78.5h
Divide both sides by 78.5: 1004.8/78.5 = 78.5h/78.5 12.8 = h