Similarity & Scale Factors

Similar figures preserve shape and corresponding angles while every corresponding length scales by one factor; areas therefore scale by the square of that factor.

What you'll learn

  • Identify a common scale factor across corresponding lengths.
  • Match corresponding sides by position and angle structure rather than arbitrary size order.
  • Distinguish similarity from congruence.
  • Explain why perimeter scales by k and area by k².
  • Use area ratios inside nested similar figures.

Before you start

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