The Lesson

The area of a rectangle is found using the formula:

In this formula, b is the length of the base of the rectangle and h is the height of the rectangle. The image below shows what we mean by the length of the base and the height:

How to Find the Area of a Rectangle

Finding the area of a rectangle is easy.

Question

What is the area of a rectangle with a base of 8 cm and a height of 5 cm, as shown below?

Step-by-Step:

1

Start with the formula:
Area = bh
Don't forget: bh = b × h

2

Substitute the length of the base and the height into the formula. In our example, b = 8 and h = 5.
Area = 8 × 5 = 40 cm2

Answer:

The area of the rectangle with a base of 8 cm and a height of 5 cm is 40 cm2.

"Find the Area" Widget

Here is a widget to help you learn the formulas to find the areas of different shapes.

Lesson Slides

The slider below shows another real example of how to find the area of a rectangle.

What Is a Rectangle?

A rectangle is a flat shape with four straight sides and four right angles. The opposite sides are parallel and of equal length. Adjacent sides are perpendicular and of unequal length.

A Note on Units

The area of a rectangle is a length times a length, so we say its dimension is length2. (All areas are lengths squared). This affects the units used. If the lengths of a rectangle are in cm, the area is in cm2. If the lengths are in inches, the area is in inches2.