By the end of the lesson the learner can apply Pythagoras' theorem to right-angled triangles.
By the end of the lesson the learner can use sine, cosine and tangent to find sides and angles.
By the end of the lesson the learner can solve real height and distance problems.
Audio narration — reads aloud, works offline
Transcript
[0:00] Pythagoras' theorem applies only to right-angled triangles, relating the three sides.
[0:45] The square on the longest side, the hypotenuse, equals the sum of the squares on the other two sides.
[1:30] Trigonometry uses ratios of sides: sine, cosine and tangent of an angle.
[2:15] Tangent is opposite over adjacent, sine is opposite over hypotenuse, and cosine is adjacent over hypotenuse.
[3:00] We use these ratios to find the height of a tree or the distance across a river without measuring directly.
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