As a relief from all the "please do my homework" messages, let's see who really knows their axe from their eblow around here.
Consider a cylindrical tank, 1 meter in diameter and 4 meters long, laid horizontally on its side. The area of the circular end is pi/4 square meters, so the capacity is pi cubic meters or about 3140 liters.
There is a sensor in the tank to measure the depth of the liquid. It has a 12-bit digital output, giving a range from 0 (0 meters deep) to 4095 (1 meter deep).
Using this depth number as input, devise an equation to calculate the volume of liquid in the tank to an accuracy of +/- 1 liter. Hint: this requires knowledge of integration, and the equation is hideous.
Now write a program to do it, on the micro of your choice, in assembly language. Do this from first principles in 4096 bytes or less, WITHOUT using a floating point library, or any pre-written trig functions, or a lookup table.
If there's any interest in this problem, I'll explain my solution a bit later on, but take a shot at it first.