### Theory:

A closed figure with three sides is a triangle.

We may classify triangles based on their sides and angles.

Let us look at each one of them in detail.

The naming of triangles based on sides

Type 1:

**Equilateral triangle**A triangle with all three equal sides is an equilateral triangle.

Here, \(\overline{AB} = \overline{BC} = \overline{AC}\).

In other words, all sides of triangle \(ABC\) are equal.

**:**

**Type 2****Isosceles triangle**

A triangle with two equal sides and a third unequal side is an isosceles triangle.

Here, \(\overline{AB} = \overline{AC}\)

Two sides of the triangle \(ABC\) are equal while the third side is unequal.

**Scalene triangle**

A triangle with all three unequal sides is a scalene triangle.

Here, the three sides \(AB\), \(BC\) and \(AC\) are unequal.

The naming triangles based on angles

**Acute angled triangle**

If all three angles in a triangle are acute, then it is an acute angled triangle.

**Right angled triangle**

If one of the angles of the triangle is 90^circ, then it is a right angled triangle.

**Obtuse angled triangle**

If any one of the angles is obtuse, then it is an obtuse angled triangle.