Classification of triangles

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Triangles differentiated on the basis of their sides

Equilateral Triangles:

picture of equilateral triangle A triangle with all sides equal to one another is called an equilateral triangle.

Isosceles Triangle:

A triangle with a pair of equal sides is called an isosceles triangle.

KOER Triangles html m34248090.png

Scalene 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.

KOER Triangles html m62898a77.png

Right angle triangle

KOER Triangles html m732d9c3d.png A right triangle has one angle 90°

Right Isosceles Triangle

KOER Triangles html m37b6213c.png If a triangle has a right angle (90°), and also two equal angles, can you guess what the equal angles are?

The Obtuse Triangle

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. KOER Triangles html m55b3a2cf.png

Exterior Angles of a triangle

An exterior angle is formed by extending any side of the triangle. KOER Triangles html 9fb9ff3.png


Image Acknowledgement: Mathsisfun.com