Class 6 Maths Understanding Elementary Shapes Classification of Triangle

Classification of Triangle:

The triangle can be classified into two groups based on their sides and angles.

Naming triangles based on sides

If in a triangle, all three sides are unequal, then it is called a Scalene Triangle.

If in a triangle, any two sides are equal, then it is called an Isosceles Triangle.

If in a triangle, all three sides are equal, then it is called an Equilateral Triangle.   Naming triangles based on angles

If each angle is less than 90°, then the triangle is called an acute angled triangle.

If any one angle is a right angle then the triangle is called a right angled triangle.

If any one angle is greater than 90°, then the triangle is called an obtuse angled triangle.   Problem: Name each of the following triangles in two different ways: (You may judge the nature of angle by observation) Solution:

(a) Acute angled triangle and Isosceles triangle

(b) Right-angled triangle and scalene triangle

(c) Obtuse-angled triangle and Isosceles triangle

(d) Right-angled triangle and Isosceles triangle

(e) Equilateral triangle and acute angled triangle

(f) Obtuse-angled triangle and scalene triangle

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