First figure the ratio of the real building to the model which is 21 divide 3. So the ratio is 1:7, since we're finding the height of the model, we divide 7 by 84 which is 12
Volume of a cylinder=the area of the base multiply the height Cylinder A's volume: pi*6*6*h=36*pi*h Cylinder B's volume: pi*3*3*h=9*pi*h so the fraction is 9/36=1/4 <span />
