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125 LearnersLast updated on December 11, 2025
Lateral Surface Area of a Triangular Prism
A triangular prism consists of two triangular bases and three rectangular lateral surfaces. The lateral surface area represents the total area of the three rectangular sides. Consider a tent with a triangular cross-section; the fabric covering the sides is akin to the lateral surface area of the tent, excluding the triangular ends.
What is the Lateral Surface Area of a Triangular Prism?
The lateral surface area of a triangular prism is the sum of the areas of the three rectangular sides of the prism.
How to Find Lateral Surface Area of a Triangular Prism
To find the Lateral Surface Area of a Triangular Prism, follow these steps:
Step 1: Identify the given parameters, such as the dimensions of the base and the height of the prism.
Step 2: Ensure all measurements are in the same unit before calculation.
Step 3: Calculate the perimeter of the triangular base and multiply it by the height of the prism using the formula: Area = Perimeter of base × height.
Step 4: Provide the calculated answer in square units.
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Tips and Tricks to Master Lateral Surface Area of a Triangular Prism
Here are some helpful strategies and advice to ensure the correct evaluation of the LSA of a triangular prism:
Double-check the values of the triangle sides to accurately calculate the perimeter.
Ensure the measurements for the height of the prism are consistent with the base dimensions.
Practice with different sets of problems to gain confidence.
Always use consistent units before writing the final answer.
Avoid rounding immediate values to maintain accuracy.
Common Mistakes and How to Avoid Them in the Lateral Surface Area of a Triangular Prism
There are a few typical mistakes people make while calculating the lateral surface area of a triangular prism.
Some of them are listed below:
Mistake 1
Confusing the base area with the lateral surface area.
The base area refers to the area of one of the triangular bases, whereas the lateral surface area involves the three rectangular sides of the prism.
Mistake 2
Incorrect perimeter calculation.
Ensure the perimeter of the triangular base is calculated correctly by summing up the lengths of all sides.
Mistake 3
Not mentioning the units with the numerical value.
It's essential to mention the unit with the answer, even if the question doesn't specify the unit.
It's preferable to write “square units” as a unit for standard representation.
Mistake 5
Mixing up lateral surface area with total surface area.
Lateral surface area refers to the area of the rectangular sides, while total surface area includes both the lateral area and the areas of the two triangular bases.
Solved Examples on Lateral Surface Area of a Triangular Prism
Problem 1
What is the lateral area of a triangular prism with a triangular base perimeter of 12 cm and a height of 10 cm?
120 cm²
Explanation
Given: Perimeter of base = 12 cm, Height of prism = 10 cm
LSA = Perimeter × height = 12 × 10 = 120 cm²
Problem 2
A triangular prism has a base with sides measuring 3 cm, 4 cm, and 5 cm, and a height of 15 cm. Find the lateral surface area.
180 cm²
Explanation
Given: Sides of base = 3 cm, 4 cm, 5 cm Height = 15 cm
Perimeter of base = 3 + 4 + 5 = 12 cm
LSA = Perimeter × height = 12 × 15 = 180 cm²
Problem 3
Calculate the lateral surface area of a triangular prism with a base perimeter of 20 cm and a height of 8 cm.
160 cm²
Explanation
Given: Perimeter of base = 20 cm Height of prism = 8 cm
LSA = Perimeter × height = 20 × 8 = 160 cm²
Problem 4
Evaluate the height of a triangular prism if its base perimeter is 14 units and its lateral surface area is 98 square units.
7 units
Explanation
Given: Perimeter of base = 14 units, LSA = 98 square units
LSA = Perimeter × height
98 = 14 × height
Height = 98/14 = 7 units
Problem 5
The lateral surface area of a triangular prism is 240 cmยฒ, and its height is 12 cm. What is the perimeter of the base?
20 cm
Explanation
Given: LSA = 240 cm² Height = 12 cm
LSA = Perimeter × height
240 = Perimeter × 12
Perimeter = 240/12 = 20 cm
FAQโs on Lateral Surface Area
1.What is Lateral Surface Area?
2.How to calculate the lateral surface area?
3.Is the lateral surface area the same as the total surface area?
4.How does the LSA change if the height of the prism is doubled?
5.What role does the perimeter of the base play in calculating LSA?
Important Glossary for Lateral Surface Area
- Triangular Prism: A 3D shape with two triangular bases and three rectangular sides.
- Perimeter: The total length around a two-dimensional shape.
- Height of Prism: The distance between the two triangular bases.
- Rectangular Side: One of the three rectangles forming the lateral surface of the triangular prism.
- Total Surface Area: The sum of the lateral surface area and the areas of the two triangular bases.
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
