Scalene Triangle — free printable diagram

What is a scalene triangle?

A scalene triangle has three sides of different lengths and, as a result, three angles of different sizes. It is the least special of the triangles — no equal sides, no equal angles and no lines of symmetry — but its angles still add up to 180°, as they do in every triangle.

Sides

3

Equal sides

None

Equal angles

None

Angles add up to

180°

Lines of symmetry

0

Rotational symmetry

Order 1 (none)

• Different side lengths force different angles: the largest angle always sits opposite the longest side, and the smallest opposite the shortest.
• A scalene triangle has no lines of symmetry, so folding it can never match one half onto the other.
• It can still be right-angled or obtuse — scalene describes the sides, not the angles, so the two classifications are independent.
• “Scalene”, “isosceles” and “equilateral” sort triangles by side length; “acute”, “right” and “obtuse” sort them by angle. Every triangle has one label from each list.