Properties of shapes

For grown-ups: this lesson in words

Years 3 to 6 · Maths

Properties of shapes: I can name and sort shapes by their sides, angles, lines and symmetry.

1. Here are 3 triangles. Every triangle has 3 straight sides and 3 corners.

   A has 3 sides all the same length. It is an equilateral triangle.

   B has 2 sides the same length. It is an isosceles triangle.

   C has 3 sides all different lengths. It is a scalene triangle.

   Picture: 3 shapes. 1: A: an equilateral triangle with its 3 sides marked. 2: B: an isosceles triangle with its 3 sides marked. 3: C: a scalene triangle with its 3 sides marked.

2. A shape with 4 straight sides is a quadrilateral. A and B are both quadrilaterals.

   A is a square: 4 equal sides and 4 right angles.

   B is a rectangle: 4 right angles too, but 2 long sides and 2 short sides.

   Picture: 2 shapes. 1: A: a square with its 4 right angles marked. 2: B: a rectangle with its 4 right angles marked.

3. C and D are quadrilaterals too: 4 straight sides each, but no right angles.

   C is a rhombus: 4 equal sides, but no right angles. It leans over.

   D is a parallelogram: opposite sides are the same length and parallel. No right angles.

   Picture: 2 shapes. 1: C: a rhombus with its 4 sides marked. 2: D: a parallelogram with its 4 sides marked.

4. Your turn: This shape has 4 equal sides and 4 right angles. What is it called?

   Picture: A flat shape with 4 straight sides, all the same length, and 4 square corners.

   Choose one:

   • rectangle
   • square
   • rhombus

   Answer

   The answer: square

   It is a square. 4 equal sides and 4 right angles make a square.

   Picture: A square with its 4 right angles marked.

Words to know

quadrilateral:

A flat shape with 4 straight sides.

parallel:

Lines that stay the same distance apart and never meet.

perpendicular:

Lines that meet at a right angle.

regular:

All the sides are equal and all the angles are equal.

vertex:

A corner point. More than one are called vertices.

line of symmetry:

A fold line that cuts a shape into two halves that match exactly.