P4 Rectangle and square measurement
find a rectangle side from perimeter
A rectangle has perimeter 28 cm and length 8 cm. Find its width.
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The pattern behind it: Rectangle and square measurement
Use opposite equal sides, undo the area or perimeter formula, and count each outside edge once.
In this one. A rectangle has two lengths and two widths. Halving the perimeter exposes one of each.
How to spot it
Squares tiling a rectangle, or a shape made of several rectangles joined together, point here. The question asks for area, perimeter, or the length of a missing side.
Common mistake
Children multiply length by width when the question actually asks for perimeter. On a composite shape, they add only the labelled sides and miss the ones they must work out themselves.
Try one like it
Standard find a rectangle side from area A rectangle has area 63 cm² and length 9 cm. Find its width.The 33 problem patterns
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
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