Classification of triangles
Triangles differentiated on the basis of their sides
A triangle with all sides equal to one another is called an equilateral triangle.
A triangle with a pair of equal sides is called an isosceles triangle.
A triangle in which all the sides are of different lengths and no two sides are equal, the triangle is called a scalene triangle.
Triangles differentiated on the basis of their angles.
Acute angled triangle.
A triangle whose all angles are acute is called an acute-angled triangle or simply an acute triangle.
Right angle triangle
A right triangle has one angle 90°
Right Isosceles Triangle
If a triangle has a right angle (90°), and also two equal angles, can you guess what the equal angles are?
The Obtuse Triangle
The Obtuse Triangle has an obtuse angle (an obtuse angle has more than 90°). In the picture on the left, the shaded angle is the obtuse angle that distinguishes this triangle. Since the total degrees in any triangle is 180°, an obtuse triangle can only have one angle that measures more than 90°.
* for geogebra link on types of triangles [click here ]
Angles in a triangle
Interior angles of a triangle
The interior angles are those on the inside of the triangle.
Exterior Angles of a triangle
An exterior angle is formed by extending any side of the triangle.
Image Acknowledgement: Mathsisfun.com