Find the area of square

The formula to find the area of square is as follows.

Area of square = square of length (i.e. L x L)
where
L is length of sides.

Find the area of rectangle

The formula to find the area of rectangle is given as.

Area of Rectangle = w x h

where
w is width.
h is height.

Find the area of triangle

To find the area of triangle we will use following formula.

Area of triangle = 1/2 x b x h
where:
b is base.
h is height.

Area of circle

The formula to find the area of circle is given below.

Area of Circle = pi x square of radius (r)

value of pi = 3.14.
Radius (r) = your desired value.