Home > Pre-Algebra > Area > Area of 2D Shapes

## Area of 2D Shapes

#### Introduction

A 2D (or two-dimensional) shape is a shape that has a length and a width, and no other dimensions. 2D shapes are, therefore, ‘flat.’ If you draw a square on a piece of paper, you have drawn a two-dimensional shape.

The area of a 2D shape is the total amount of space is contains. If you build a fence around a field, the area of the field is the amount of land in the field. Depending on the shape of the field, you can calculate the area in different ways.

## Lesson

Calculating the area of a 2D shape depends on what shape you have. However, the general rule is:

$ext{Area} = ext{Length} imes ext{Width}$

The simplest shape to calculate the area of is a square. Since all four sides are the same, length and width are the same value. Find the length of one side, multiply it by itself, and you have the area.

So, if we have a square with a side length of 3, we would do the following calculation:

$3 imes 3 = 9$

The area of the square is 9 units squared.

For a rectangle, the approach is similar to that of a square. Simply take the length of the rectangle and multiply it by the width.

If we have a rectangle with a length of 7 and a width of 4, we can calculate the area by plugging in the numbers:

$7 imes 4 = 28$

The area of the rectangle is 28 units squared.

You need to make sure that the units you are using are the same for both sides, otherwise the area will be incorrect. For example, if the length is measured in feet, and the width is measured in inches, you must make sure to convert the length to inches, or the width to feet.