|Class 7 Maths The Triangle and its Properties||Introduction|
A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. It has three vertices, three sides and three angles. A triangle with vertices A, B, and C is denoted by ∆ ABC.
Let us consider a triangle ABC.
Three sides are: AB, BC and CA
Three vertices are: A, B and C
Three angles are: ∠ABC, ∠BAC, ∠BCA
The side opposite to vertex A is BC. The side opposite to vertex B is AC. The side opposite to vertex C is AB. We can classify triangles based on sides and angles.
(i) Based on Sides: Scalene, Isosceles and Equilateral triangles.
(ii) Based on Angles: Acute-angled, Obtuse-angled and Right-angled triangles.