A glass jar is shaped like a  cylinder.  The jar for a height of 8 in. and a base with a diameter of 4in. There are 3 in. of grape jelly left in the jar.  What is the volume of the jelly in the jar?

It doesn't really matter that the jar is 8 inches high.  What matters is how high the jelly is (3 inches), so the height that matters is 3 inches.  The diameter of the jar is 4 inches.  We need to know the radius of the circle in order to find out the area of the circle, so divide the diameter in half.  So half of 4 inches is 2 inches, which is the radius.  Use the formula where the volume is equal to pi times the radius squared times the height: Volume = 3.14 *( 2)^ 2 * 3     Square the 2 firstVolume = 3.14 * 4 * 3             Multiply by 3Volume = 3.14 * 12                Then multiply by pi (3.14)Volume = 37.68(If you round it to more than the hundredth for pi, like 3.14159, then your answer would be 37.69908)(If you use 3.141592653589 for pi, then Volume = 37.699111843068, etc.)