SOHCAHTOA - Sine, cosine and tangent in right angle triangles

Reason For Learning

You can use trigonometric ratios, sine, cosine and tangent, to find unknown side lengths in right angled triangles or the angles in right angled triangles. Knowledge of the ratios is a basic skill used for problem solving in a lot of situations where triangles are involved.

Learning Intention

For a right angled trianle, what the sine, cosine and tangent ratios are defined as. How to explain why the ratios of matching sides in similar right angled triangles are constant for equal angles. How to use trigonometric notation (eg sinA). How the mnemonic SOHCAHTOA helps you remember the trigonometric ratios

Key Vocabulary Terms

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    ACMMG223 Level 9

    Use similarity to investigate the constancy of the sine, cosine and tangent ratios for a given angle in right-angled triangles

    ACMMG224 Level 9

    Apply trigonometry to solve right-angled triangle problems