### 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.

Type 3: 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
Type 1: Acute angled triangle

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

Type 2: Right angled triangle

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

Type 3: Obtuse angled triangle

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