Integral

Do you know integral? Integral is very important to calculate a volume or area.
This is an example of calculation using integral

A ball is filled by water until 5/7 of height. Calculate the volume of ball if the radius of the ball is 7 cm














Okay. First step.
We would to divide this ball becoming 2 frustum. A and B













We know that volume A is 1/2 * 4/3 * phi * R^3
So volume A = 1/2 * 4/3 * 22/7 * 7 * 7 * 7
volume A = 718.67 cm3


For volume B, we will use integral
we know that x^2 + y^2 = r^2 (Pythagoras)


Volume B =









So total volume water is volume A + volume B = 856.67 cm3