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Classify Triangle by Side Lengths: Equilateral, Isosceles, or Scalene
Published on May 13, 2026
Geometry
Learn how to classify a triangle as equilateral, isosceles, or scalene based on its side lengths. This problem uses a triangle with sides 17, 18, and 19.
Question
Answer
The problem asks us to classify the triangle based on its side lengths.
The image shows a triangle with side lengths labeled as 17, 19, and 18.
The image shows a triangle with side lengths labeled as 17, 19, and 18.
We need to classify the triangle into one of the following categories:
- Equilateral triangle: A triangle with all three sides of equal length.
- Isosceles triangle: A triangle with at least two sides of equal length.
- Scalene triangle: A triangle with no sides of equal length.
Let’s examine the given side lengths: 17, 19, and 18.
Compare the side lengths:
- Is 17 equal to 19? No.
- Is 17 equal to 18? No.
- Is 19 equal to 18? No.
Since all three side lengths are different (17
Based on the definitions:
- Since not all sides are equal, it is not an equilateral triangle.
- Since no two sides are equal, it is not an isosceles triangle.
- Since all sides are of different lengths, it is a scalene triangle.
Therefore, the triangle should be classified as scalene.
Looking at the options provided:
- Equilateral
- Isosceles
- Scalene
The correct classification for the given triangle is Scalene.
The final answer is