find the area of the rectangle ABCD where A(1,2) B(1,4) C(5,4) and D(5,2)

A(1,2) B(1,4) C(5,4) and
D(5,2)

We know that the area of the rectangle
is:

a = Length * width

Let us
calculate:

AB = sqrt(1-2)^2 + (4-2)^2 = sqrt(4 =
2

BC = sqrt[(5-1)^2 + (4-4)^2] = sqrt(16) =
4

Then :

 a = 2*4 =
8

The area of the rectangle is 8 square
units.