Is a Triangle with Sides 7 cm, 24 cm, and 25 cm a Right Triangle? A Clear Geometry Check

When studying triangles, one common question students face is whether a three-sided figure with given side lengths — such as 7 cm, 24 cm, and 25 cm — is a right triangle. In this article, we’ll clearly explain how to determine if this triangle satisfies the key condition of being a right triangle and verify its classification using the Pythagorean theorem.

What is a Right Triangle?

Understanding the Context

A right triangle is defined as a triangle that contains one angle measuring exactly 90 degrees. The side opposite this right angle is called the hypotenuse, the longest side of the triangle. For a triangle with sides a, b, and c (where c is the longest side), it is a right triangle if:

\[
a^2 + b^2 = c^2
\]

This is the well-known Pythagorean Theorem.


Key Insights

Analyzing the Given Triangle

We are given side lengths: 7 cm, 24 cm, and 25 cm.

First, identify the longest side:
- 7 cm < 24 cm < 25 cm ⇒ The longest side is 25 cm, which we assume could be the hypotenuse.

Now, apply the Pythagorean theorem to test:

\[
7^2 + 24^2 = ?
\]
\[
49 + 576 = 625
\]

Final Thoughts

\[
25^2 = 625
\]

Since both expressions are equal:

\[
7^2 + 24^2 = 25^2
\]

This confirms the triangle satisfies the Pythagorean Theorem.


Conclusion: Yes, It Is a Right Triangle

Because the squares of the two shorter sides (7 cm and 24 cm) add up exactly to the square of the longest side (25 cm), this triangle is a right triangle. It has a right angle opposite the 25 cm side, making it a classic example of a 7-24-25 right triangle — one of the well-known Pythagorean triples.


Why This Matters

Understanding whether triangles like this are right-angled is fundamental in geometry, trigonometry, architecture, engineering, and math education. Recognizing right triangles helps in calculating area, verifying structural stability, and solving real-world problems involving angles and distances.