MATHS:Classifications of Triangles

RIGHT TRIANGLE

A right triangle has one 90° and a variety of often-studied properties including:

• Right Triangle Calculator
• Proof of Pythagorean Theorem
• Pythagorean Triplets
• Sine, Cosine, Tangent
• Pictures of Right Triangles
• 7 24 25 Right Triangle Images
• 3 4 5 Right Triangles
• 5 12 13 Right Triangles

EQUILATERAL TRIANGLE

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

Each angle is 60°.

ISOSCELES TRIANGLE

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

SCALENE TRIANGLE

The Scalene Triangle has no congruent sides. In other words, each side must have a different length.

ACUTE TRIANGLE

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

OBTUSE TRIANGLE

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.

Since the total degrees in any triangle is 180°, an obtuse triangle can only have one angle that measures more than 90°.