Types of triangles- Right, Acute, Obtuse….. 

        Type on triangles on base of angles

1.  Right triangle: If in a triangle, one angle is 90 degree, the triangle called right triangle.

^or 

A right triangle has a 90⁰  angle.

The following triangle is a right triangle. 

2. Acute triangle: If in a triangle, all three angles are less than 90 degree, the triangle called acute triangle

or

An acute triangle has three acute angles, or in an acute triangle, all angles are less than 90 degree, so all angles are acute angles.

The following triangle is a acute triangle.  

3. Obtuse triangle: If in a triangle, one angle is more than 90 degree, the triangle called Obtuse triangle.

                                or

An obtuse triangle has an obtuse angle, an obtuse angle, has more than (90 degree).

The following triangle is a obtuse triangle.  

        Type on triangles on base of sides

1. Equilateral triangle:  If in a triangle, all three angles are equal, and each angles are 60 degree, the triangle called equilateral triangle.

The following triangle is an equilateral triangle.  

2. Isosceles triangle: If in a triangle, two angles are equal and two sides are equal, the triangle called isosceles triangle.

The following triangle is a isosceles triangle.  

3. Scalene triangle: If in a triangle, any angles and any sides are not equal, the triangle called scalene triangle. in other words, each side have different length and each angle must have a different degree.

 The following triangle is a scalene triangle.  

4. Right Isosceles triangle: If in a triangle one right angle and two angles and two sides are equal, the triangle called right isosceles triangle.

 The following triangle is a right Isosceles triangle.