2D Shapes (WJEC GCSE Maths & Numeracy (Double Award)): Revision Note

Properties of 2D shapes

What are the names of common 2D shapes?

• You should know the general names of all the 2D polygons

  • A triangle has 3 sides

  • A quadrilateral has 4 sides

  • A pentagon has 5 sides

  • A hexagon has 6 sides

  • A heptagon has 7 sides

  • An octagon has 8 sides

  • A nonagon has 9 sides

  • A decagon has 10 sides

  • A polygon is a flat (plane) shape with n straight sides

    • A regular polygon has all sides the same length and all angles the same size  

What are the names of the different types of triangles?

• You should know the names and properties of the different types of triangles

  • An equilateral triangle has 3 equal sides and 3 equal angles

  • An isosceles triangle has 2 equal sides and 2 equal angles

  • A right-angled triangle has one 90° angle

  • A scalene triangle has 3 sides all of different lengths

What are the names of the different types of quadrilaterals?

• You should know the names and properties of the different types of quadrilaterals

  • These are squares, rectangles, parallelograms, rhombuses, trapeziums and kites

What are the properties of rectangles and squares?

• A square is a rectangle where all the sides have the same length

• The table below shows the properties of a rectangle and square

What are the properties of parallelograms and rhombuses?

• A rhombus is a parallelogram where all the sides have the same length

• The table below shows the properties of a parallelogram and rhombus

What are the properties of trapeziums?

• The table below shows the properties of a trapezium and an isosceles trapezium

What are the properties of kites?

• The table below shows the properties of a kite

What terms related to circles do I need to know?

• Circles have several specific terms that you need to be familiar with:

  • A circle's perimeter is called a circumference

  • Its line of symmetry is called a diameter

  • The line from the centre of the circle to its circumference is called a radius

    • The diameter is equal to 2 × the radius

  • A portion of the circumference is called an arc

  • A portion of the area, contained between two radii and an arc, is called a sector

  • A line between two points on the circumference is called a chord

  • The area formed between a chord and an arc is called a segment

  • A line which intersects the circumference at one point only, is called a tangent

• The ratio  is equal to 𝝅 (3.14159...)

• Circles have many angle properties and you will need to learn some of them

  • These properties are known as circle theorems