Perimeter with composite rectilinear shapes

Maths

In this unit pupils learn how to derive and use the formula for the area of a triangle and trapezium. In the future unit, this knowledge is called upon to find the volume of different prisms and area of composite shapes

In this unit, pupils explored the relationship between perimeter and area. In particular, they considered whether a shape can have the same area and perimeter value

Perimeter and area

True or false? A composite shape is an alternative term for a compound shape.

A {{}} shape is a shape created using two or more basic shapes.

A composite rectilinear shape is made from ______

What is the length of the side marked $$a$$ in the diagram?

What is the length of the side marked $$b$$ in the diagram? 

Mariam wants to fence in a pentagonal garden. Each side of the pentagon measures 6 meters. What is the perimeter of Mariam's garden?

Mia wants to enclose her garden in the shape of an irregular hexagon. The lengths of the sides of the hexagon are 5 m, 7 m, 4 m, 6 m, 9 m, and 8 m. What is the perimeter of Emma's garden?

Alex wants to frame a triangular picture. The lengths of two sides of the triangle are 80 cm and 120 cm. If the perimeter of the triangle is 350 meters, what is the length of the third side?

Jun wants to build a rectangular pond in his backyard. The pond has a length of 2.6 m and a perimeter of 8.6 meters. What is the width of the pond?

This lesson will be removed by end of Summer Term 2025.

Perimeter with composite rectilinear shapes

Lesson outcome

This lesson will be removed by end of Summer Term 2025.