Skill: Find missing dimensions from area

The area of a rectangle tells how many square units cover it. For a rectangle,

$$\text{area}=\text{length}\times\text{width}.$$

If one side is missing, divide the area by the known side:

$$\text{missing side}=\text{area}\div\text{known side}.$$

Example: A rectangular garden has an area of $24$ square meters. Its length is $6$ meters. What is its width?

1. Write what you know:

$$\text{area}=24,\qquad \text{length}=6,\qquad \text{width}=?$$

2. Divide the area by the known length:

$$24\div 6=4$$

3. The width is $4$ meters.

You can picture this as an array with $6$ columns and $4$ rows. It has $24$ squares altogether.

Check your answer with multiplication:

$$6\times 4=24$$

Since the product matches the area, the width is correct. Remember, area uses multiplication of the two side lengths; it is not the distance around the rectangle, which is the perimeter.