Polygons

Understanding Polygons

  • Be aware of what a polygon is: a shape that is made up of straight lines and is fully closed.
  • Recognise that polygons can be both regular (all sides and angles are equal) and irregular (not all sides and angles are equal).
  • Understand that polygons are convex (all interior angles less than 180 degrees) or concave (at least one interior angle greater than 180 degrees).

Types of Polygons

  • Identify and describe types of polygons: triangle (3 sides), quadrilateral (4 sides), pentagon (5 sides), hexagon (6 sides) and so on.
  • Understand specific types of quadrilaterals, including squares, rectangles, parallelograms, trapeziums, kites, and rhombuses.

Properties of Polygons

  • Recall the sum of the interior angles of a polygon, which is given by the formula (n-2) x 180, where n is the number of sides.
  • Calculate a missing interior or exterior angle in a polygon using the rules on the sum of angles.
  • Understand the differences and similarities between polygons, such as how a square is a rectangle, but not all rectangles are squares.

Area of Polygons

  • Derive and apply the formula to calculate the area of regular polygons.
  • Understand how to decompose irregular polygons into regular shapes to calculate their area.
  • Be able to calculate the area of triangles and rectangles, and extend this to parallelograms and trapeziums.

Transformations of Polygons

  • Recognise how polygons can be transformed through rotations, translations, reflections and enlargements.
  • Understand the properties of polygons that are preserved under each transformation.
  • Determine congruent and similar polygons by considering transformations.