Study notes

Pythagoras' Theorem & Trigonometry

Pythagoras' theorem (including its converse) and the sine, cosine, and tangent ratios for right-angled triangles.

What this topic covers

  • Pythagoras' theorem relates the two legs and the hypotenuse
  • Finding a missing leg means subtracting, not adding
  • The converse checks whether a triangle is right-angled at all
  • The three trig ratios link an angle to a pair of sides
  • Pick the ratio that matches the two sides you actually have
  • Finding an unknown angle uses the inverse ratio

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