Parallelograms & Trapeziums Magic tricks with rectangles!
Area of a Parallelogram perpendicular height What can you say about the base, height and area of the parallelogram compared with the rectangle base
Area of a Parallelogram Area of a parallelogram = Area of a rectangle = base x height = bh Remember the height and base must be perpendicular measurements
Sneaky Ones! Sometimes they try and catch you out. 6 6 7 4 8 5 9 Look for two measurements that are perpendicular to each other 12 8
? What will be the base of the new rectangle? If you are not sure then try it with some different values for a and b to see what happens. Area of a Trapezium a h b
Area of a Trapezium Area of a Trapezium = ½ (a+b)h Notes: Add a and b first then times by the height and divide by 2. a and b are the parallel sides and h is the perpendicular distance between them – this is not necessarily the height.
5 8 9 5 4 15 A trapezium is not necessarily a roof shape! Sometimes it is a lean-to conservatory and sometimes it is nothing to do with houses at all! Identify a, b and h. Then find the areas