To find the area of an irregular object you need to measure how much liquid goes into it. You should measure how much water goes into the object by pouring water into a graduated cylinder, and then pour water into the irregular object.

Okay, so lets sat that we fill up the graduated cylinder, or beaker with 2000 milimeters.Then we pour the water into the irregular object. If the object is full, than that means its volume is 200 cubic centimeters. If it is not right then you keep measuring how much water you put.