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# Shape

Triangles

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Triangles have three sides. There are many different types of triangles:

## Equilateral triangle

• 3 equal sides

• 3 equal angles of 60° ## Isosceles triangle

• 2 equal sides

• 2 equal angles ## Scalene triangle

• No equal sides

• No equal angles ## Right-angled triangle

• One of its angles is a right angle (90°) ## Square

• 4 equal sides

• 4 right angles ## Rectangle

• 2 pairs of equal sides

• 4 right angles ## Rhombus (squashed square)

• 4 equal sides

• Opposite sides are parallel

• Opposite angles are equal ## Parallelogram (squashed rectangle)

• 2 pairs of equal sides

• Opposite sides are parallel

• Opposite angles are equal ## Trapezium

• One pair of parallel sides of different lengths ## Kite

• 2 pairs of equal sides next to each other

• No parallel sides. Circles

All circles have a circumference, diameter and radius:

• The circumference is the distance all the way around a circle.

• The diameter is the distance right across the middle of the circle.

• The radius is the distance halfway across the circle. The radius is always half the length of the diameter. Polygons

Polygons are shapes with many straight sides:

• Regular polygons have equal angles and sides of equal length.

• Irregular polygons have sides of different lengths.

Here are some common polygons:

## A regular pentagon ## An irregular pentagon ## A regular hexagon ## An irregular hexagon ## A regular heptagon ## An irregular heptagon ## An irregular Octagon Top