Triangle
Definition of Triangle
- A three-sided polygon is called to be a triangle.
- A Triangle is a polygon with three sides.
More about Triangles
- Equilateral Triangle: A triangle with all the sides of same length is called equilateral triangle.
- Isosceles Triangle: A three-sided polygon with at least two sides of the same length is called isosceles triangle.
- Scalene Triangle: A three-sided polygon with no sides of the same length is called scalene triangle.
- Right Triangle: A three-sided polygon with one right angle is called right triangle.
- Acute Triangle: A triangle measuring all its angles less than 90o is called acute triangle.
A three-sided polygon with all its angles less than 90o is called acute triangle.
- Obtuse Triangle: A triangle with one of its angle measuring more than 90o is called obtuse triangle.
Examples of Triangle

Solved Example on Triangle
A piece of land is in the shape of a triangle with the sides of length 5 m, 5 m and 3 m?
What is this triangle called?
Choices:
A. right triangle
B. scalene triangle
C. isosceles triangle
D. equilateral triangle
Correct answer: C
Solution:
Step 1: Two of the three sides are equal to 5 m.
Step 2: Since two sides are equal, the land is in the form of an isosceles triangle.
Related Terms for Triangle
- Polygon
- Three-sided figure