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
, wheren
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.