Question

class 7maths NCERT chapter 6​

Answer 1

Triangle: A triangle is a simple closed curve made of three line segments. It has three vertices, three sides and three angles.

Classification of triangles based on sides

A triangle having three unequal sides is called a scalene triangle.

A triangle having two equal sides is called an isosceles triangle.

A triangle having three equal sides is called an equilateral triangle.

Classification of triangles based on angles

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

If anyone angle is a right triangle, then the triangle is called a right-angled triangle.

If anyone angle is greater than 90°, then the triangle is called an obtuse-angled triangle