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Similar shapes have the same shape but can be different sizes. Their corresponding angles are equal, and every corresponding length is changed by the same scale factor.
To find corresponding sides, match the vertices first, then compare sides in the same positions. This matters when a shape has been rotated, reflected, or labelled in a different order.
If one side is multiplied by kkk, every other corresponding side is also multiplied by kkk. This is the key length rule in every similar-shapes question.
Question 1
3 marksAB AB\,AB is parallel to XYXYXY. The lines AY AY\,AY and BX BX\,BX intersect at PPP. AB=6AB = 6AB=6 cm. XP=12.5XP = 12.5XP=12.5 cm. XY=15XY = 15XY=15 cm.
What two conditions must be met for two shapes to be mathematically similar?
Revision notes for Edexcel GCSE Maths Similar Shapes (Lengths). Open the guide for explanations and worked examples. Written against the Edexcel GCSE Maths (1MA1) specification, so the content matches what's examinable rather than general Maths background.
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Two similar triangles have corresponding sides of 999 cm and 151515 cm. If another side of the smaller triangle is 121212 cm, what is the corresponding side of the larger triangle?
