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91�ȱ� Teach > Primary Resources > KS2 Maths > Neon City: Measurement and Geometry

Zach and Kayla are pleased with their virtual house design, but something is missing – windows!

Ada explains that they need to work out the perimeter of the windows they want, so they know how much wood they need to build them. Ada explains that perimeter is the length of the lines around a closed 2D shape, like the frame around a window.

Zach starts to work out the perimeter of the window they want by measuring the sides with a ruler. Ada explains that a quicker way is to remember that rectangles always have two pairs of equal sides, so they can measure one length and width and multiply both by two.

They then apply this knowledge to working out the perimeter of a rectangle and a square. Zach then displays his favourite window, which is a composite rectilinear shape.

The children talk through ways to work out the missing lengths in a composite shape, as well as discussing how important it is to make sure you are using the same unit of measurement for every side.

This short animated film is from the 91�ȱ� Teach series, Neon City: Measurement and Geometry.

Teacher notes

Before watching

You may wish to recap previous learning on perimeter, for example checking whether the children are able to measure the perimeter of a rectangle by counting squares or using a ruler. You may want to check for any misconceptions or common mistakes in using these methods.

During the film

Depending on the focus on your lesson, you may wish to use only the beginning of this episode, or to focus on the second half. Stop the episode in appropriate places to check for understanding, or to ask the children to repeat or explain key facts or sentences. For example, Perimeter is the length of the lines around a closed 2D shape. You could use the calculation that Zach formulates when working out the perimeter of the window, and ask the children to apply this to another shape, e.g. 100cm x 2 + 50cm x 2= 300cm.

As Zach and Kayla try to work out the perimeter of the composite shape, stop the film and ask your pupils to work it out before they do. What might be the tricky aspects of this? Where might they go wrong?

After watching

You might want to ask the children to design their own virtual house, with their own ideal windows, which can be any rectangular or composite shape they like. Can they work out how much wood they would need to design the windows they need?

You could provide the children with a number of examples to improve their fluency with working out the perimeter of shapes. You could also provide them with opportunities to develop their reasoning and problem solving skills, such as: the perimeter of a shape is 40cm. What length might its sides be? Or Always, Sometimes, Never: the perimeter of a shape is a higher number than the area of the same shape? Can the children provide examples to prove their answer?

(PDF, 690KB)

Curriculum notes

This short film is suitable for teaching maths at KS2 in England and Northern Ireland, 2nd Level in Scotland and Progression steps 2 and 3 in Wales.

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