Properties of Shapes

In Key Stage 2 you go much deeper into the properties of 2D and 3D shapes. You learn about angles in triangles and quadrilaterals, how to classify shapes precisely, and how to calculate angles you haven't been given.

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Types of Triangle

All triangles have 3 sides and 3 angles, and the angles always add up to 180 degrees.

Type	Properties
Equilateral	3 equal sides, 3 equal angles (each 60 degrees)
Isosceles	2 equal sides, 2 equal base angles
Scalene	All sides different, all angles different
Right-angled	One angle = 90 degrees (the other two add up to 90)

Finding a missing angle in a triangle:

• Angles in a triangle sum to 180 degrees.
• Example: a triangle has angles 70 and 55 degrees. Third angle = 180 - 70 - 55 = 55 degrees.

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Quadrilaterals

All quadrilaterals have 4 sides, and their interior angles always add up to 360 degrees.