A triangle is a plane figure with three straight sides and three angles. The sum of angles of a triangle is equal to 180 degrees and the exterior angles of a triangle are always equal to 360 degrees. In a triangle, the sum of the angles is always greater than the length of the third angle. The area of a triangle is given by the formulae:
½ * base * height.
A triangle is classified into different types based on their sides and angles.
- Equilateral Triangle
- Isosceles triangle
- Scalene Triangle
- Acute angled Triangle
- Right angle Triangle
- Obtuse-angled Triangle
Details about Chapter 7 of Class 9 Maths are given below:
Class 9 Maths Revision Notes Chapter 7- Triangles
For more information about the Triangles, click on the below-mentioned links.
| Triangles | Types Of Triangles |
| Similarity of Triangles | Similar Triangles and Similarity of Triangles |
Frequently asked Questions on CBSE Class 9 Maths Notes Chapter 7: Triangles
What are the types of triangles?
There are three main types of triangle based on the length of the sides: equilateral, isosceles and scalene.
What are ‘Similar triangles’?
Triangles that have the same shape, but their sizes may vary are called as similar triangles.
What is an ‘exterior’ angle?
The angle between any side of a shape, and a line extended from the next side is called as the ‘exterior angle’.
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