A quadrilateral is any shape with four straight sides, but the family has special members. A square has four equal sides and four right angles. A rectangle has four right angles with opposite sides equal. A rhombus has four equal sides but no right angles. A parallelogram has two pairs of parallel sides. A trapezium has exactly one pair of parallel sides, and a kite has two pairs of equal sides next to each other. To name a shape, check the sides and the angles — not how it is turned. Turning a shape never changes its name.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- quadrilateral
- a shape with four straight sides
- parallel
- always the same distance apart, never meeting
- right angle
- a square corner of 90°
Worked examples
Name the shape with four right angles, longer than it is wide.
- 1.Four right angles means it is a rectangle family shape.
- 2.Sides not all equal, so it is a rectangle.
= rectangle
Name the shape with four equal sides but no right angles.
- 1.Four equal sides.
- 2.No right angles rules out a square, so it is a rhombus.
= rhombus
Name the shape with exactly one pair of parallel sides.
- 1.Only one pair of parallel sides.
- 2.That is a trapezium.
= trapezium
For parents
Method: Sort shapes by counting equal sides and right angles.
What to say: Ask 'how many equal sides?' and 'are the corners square?' before naming it.
Common mistakes:
- Calling every four-sided shape a square.
- Saying a tilted square is a diamond — turning a shape does not rename it.