Key learning points

1. An equilateral triangle is a regular triangle and has particular properties.
2. A scalene triangle has specific properties.
3. An isosceles triangle has properties including a line of symmetry that splits it into two congruent triangles.
4. A right-angled triangle can be scalene or isosceles.

Common misconception

Keywords

• Equilateral - Equilateral triangles have three equal-sized angles and three edges of equal length. They are regular triangles.

• Scalene - Scalene triangles have three different-sized angles and three different-sized edges (sides).

• Isosceles - Isosceles triangles have two equal-sized angles and two sides of the same length.

• Right-angled triangle - A right-angled triangle has exactly one 90° interior angle.