Smart Math guide · Geometry Smarts

Use Similar Triangles for Indirect Measurement

Similar triangles have equal corresponding angles and proportional corresponding sides.

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The method

How to use it

  1. Match corresponding sides.
  2. Set up a proportion.
  3. Solve and check scale factor.
Worked example

See it in action

A 2 m stick casts a 3 m shadow; a tree casts 12 m. Height=2×12/3=8 m.

Check your thinking

How to verify it

Scale factor 12/3=4; 2×4=8.

Keep learning

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