It depends what figure you have.
The most basic shape, a square, or even a rectangle's area is found by multiplying the two different side lengths together. (length and width)
A triangle is the base * height / 2.
Trapezoid base 1 + base 2 *height / 2 or something like that.
Circle is [tex] \pi [/tex] r squared.
Just search it up for each one.