Types of Triangles

Right Triangles
 

A right triangle has one 90° and a variety of often-studied properties including: Proof of Pythagorean Theorem Pythagorean Triplets Sine, Cosine, Tangent

The Equilateral triangle shown on the left has three equal sides and three equal angles.

Each angle is 60°

 

 

 

The Isosceles triangle shown on the left has two equal sides and two equal angles.

 

 

The Scalene Triangle has no congruent sides.

 

 

The Acute Triangle has three acute angles (an acute angle measures less than 90°)

The  Obtuse Triangle has an obtuse angle (an obtuse angle has more than 90°). In the picture on the left, the shaded angle is the obtuse angle that distinguishes this triangle

What kind of triangle is pictured on the left?
   Triangle Type     Acute Triangle

What kind of triangle is pictured on the left?
   Triangle Type    
Obtuse Triangle

What type of triangle is pictured on the left?

   Triangle Type     Since this triangle has two congruent angles and two congruent sides, it is an Isosceles Triangle