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# Types of Triangles

#### Lesson Contents

## The 6 Main Types of Triangles: by Side and by Angle

Triangles types are named and classified by their sides and by their angles.

By Angle:**Acute Triangle — All angles are less than 90°.****Right Triangle — Has an angle that is exactly 90°.****Obtuse Triangle — Has one angle that is more than 90°.**

By Side:**Equilateral Triangle — All three sides are equal in length.****Isosceles Triangle — Two sides are equal in length.****Scalene Triangle — Has no sides that are equal in length.**