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103 LearnersLast updated on September 4, 2025
Surface Area of Rectangle
A rectangle is a 2-dimensional shape with opposite sides equal and four right angles. The surface area of a rectangle refers to the total area covered by its outer surface. In this article, we will learn about how to calculate the surface area of a rectangle.
What is the Surface Area of a Rectangle?
The surface area of a rectangle is the total area occupied by its boundary or surface. It is measured in square units.
A rectangle is a flat, 2D shape with two pairs of equal sides and four right angles. The surface area of a rectangle is often simply referred to as its area.
Rectangles are common in everyday life, forming the basis of many objects such as books, screens, and tables.
Surface Area of a Rectangle Formula
The formula for finding the surface area (or area) of a rectangle is straightforward. It involves the length and the width of the rectangle.
The surface area of a rectangle is calculated using the formula: Area = Length × Width
Examples of Surface Area of a Rectangle
To understand how to calculate the surface area of a rectangle, let's look at some examples:
Example 1: A rectangle has a length of 8 cm and a width of 5 cm. Find its surface area.
Solution: Area = Length × Width = 8 cm × 5 cm = 40 cm²
Common Mistakes and How to Avoid Them in the Surface Area of a Rectangle
While calculating the surface area of a rectangle is simple, students often make mistakes that lead to incorrect answers. Below are some common mistakes and ways to avoid them.
Confusion between Length and Width
Students sometimes mix up which dimension is the length and which is the width. Remember, the length is typically the longer side, but ensure to use the given measurements correctly.
Using Incorrect Units
It's important to remember that the area is always expressed in square units. If the measurements are in cm, the area will be in cm². Always square the unit after calculating the area.
Mixing Up Length and Width
Ensure you correctly identify which side is the length and which is the width. The formula requires the correct placement of these measurements.
Mistake 1
Forgetting to Square Units
Always express the area in square units. This mistake often leads to incorrect interpretation of the results.
Mistake 2
Incorrect Calculation
Double-check your multiplication, as simple arithmetic errors can lead to the wrong area calculation. Always verify your calculations.
Mistake 3
Solved Examples of Surface Area of Rectangle
Find the surface area of a rectangle with a length of 12 cm and a width of 7 cm.
Area = 84 cm²
Problem 1
Given length = 12 cm, width = 7 cm. Use the formula: Area = Length × Width = 12 cm × 7 cm = 84 cm²
Find the surface area of a rectangle with length 15 cm and width 10 cm.
Explanation
Area = 150 cm²
Problem 2
Use the formula: Area = Length × Width = 15 cm × 10 cm = 150 cm²
A rectangle has a length of 9 m and a width of 4 m. Find the surface area.
Explanation
Area = 36 m²
It is the total area covered by the rectangle, calculated as the product of its length and width.
1.How do you calculate the surface area of a rectangle?
2.Is there a difference between area and surface area for rectangles?
3.Can a rectangle's area be measured in cubic units?
4.Why is the area expressed in square units?
Common Mistakes and How to Avoid Them in the Surface Area of a Rectangle
Here are some common mistakes students make while calculating the surface area of a rectangle and ways to avoid them.
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Seyed Ali Fathima S
About the Author
Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.
Fun Fact
: She has songs for each table which helps her to remember the tables
