RD Sharma Solutions for Class 9 Maths Chapter 9 Triangle and its Angles

A triangle has three angles. The sum of the measures of the angles is always 180° in a triangle. A triangle that has one obtuse angle is called an obtuse triangle. When a triangle has three congruent sides, we call the triangle an equilateral triangle. A triangle is a 2D geometrical figure consisting of three edges and three vertices—the three angles made by the three sides of a triangle. Triangles are categorized based on their angles and sides.

Triangles categorized based on their angles: Acute Triangle, Right Angle and Obtuse Triangle.

Triangles categorized based on their sides: Scalene triangle, Isosceles triangle and Equilateral triangle.