Step 7 Objective

Deduce and use formulae for the area of a triangle, a parallelogram and a trapezium; calculate areas of compound shapes made from rectangles and triangles.


Probing questions

happy learners

Why do you have to multiply the base by the perpendicular height to find the area of a parallelogram?

Right-angled triangles have half the area of the surrounding rectangle with the same base and height. What about non-right angled triangles?

The area of a triangle is 12 cm². What are the possible lengths of the base and height?

What other formulae for the area of two-dimensional shapes do you know?

Is there a formula for every two-dimensional shape?