Let’s learn how to determine the area of a rectangle.
A rectangle is a four-sided shape with equal and parallel opposite sides. Remember that area refers to the total amount of space enclosed in a shape. The area is expressed in square units such as square meter (m2), square in (in2), or square kilometer (km2)
To find the area of a rectangle, multiply its length by its width, as expressed in the formula:
A = L • W
where L = Length of the rectangle; W = Width of the rectangle
Related Reading: Perimeter of a Rectangle – Formula & Examples
How to Compute the Area of a Rectangle:
Follow these steps to find the area.
Step 1. Write down the given measurements. Make sure the units are all the same. If not, convert either the length or the width to match the other.
Step 2. Plug the figures into the formula for area of a rectangle: A = L • W .
Step 3. Perform the operation. Don’t forget to write the measurement unit (should be a square unit) together with the answer.
Example #1: Find the Area of a Rectangle When Given Length and Width
Find the area of the rectangle below.
Solution for Example #1:
Step 1. Write down the given figures, the length (L=20cm) and width (W=3cm).
Step 2. Substitute 20cm for L and 3cm for W in the formula.
A = L • W
A = 20cm • 3cm
Step 3. Simplify.
A = 60cm²
Therefore, the area of the rectangle is 60cm².
Example #2: Find the Area of a Rectangle with Different Units
Find the area of the rectangle below.
Solution for Example #2:
Step 1. Write down the given figure, the length (L=2m) and the width (W=150cm). Convert either of them to match the measurement unit. For this example, let’s convert 150cm to m. Recall that 1m = 100cm.
Therefore, the width (W=150cm) can be converted to equal W=1.5m.
Step 2. Substitute 2m for L and 1.5m for W in the formula:
A = L • W
A = 2m • 1.5m
Step 3. Simplify.
A = 3m²
Therefore, the area of the rectangle is 3m².
Example #3: Find the Width of a Rectangle when Given Length and Area
Find the width of the rectangle below.
Solution for Example #3:
Step 1. Write down the given figure, the length (L=60cm) and the area (A=930cm²). Find the width by dividing the area formula by the length.
A = L • W
A / L = (L • W) / L
A / L = W
Therefore, to compute the width, divide the area by the length.
Step 2. Substitute 930cm² for A and 60cm for L in the formula:
W = A / L
W = 930cm² / 60cm
Step 3. Simplify.
W = 15.5cm
Therefore, the width of the rectangle is 15.5cm.
Thank you for reading. We hope it’s effective! Always feel free to revisit this page if you ever have any questions about the area of a rectangle.
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