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Similar triangles and ratios – sin, cos and tan
In the right-angled triangle below, the green side is called the hypotenuse.
For the reference angle given in blue, the blue side is called the opposite side.
The red side is called the adjacent side.
Pick an angle and stick with it.
Work out the value of \(\dfrac{\color{Blue}{opposite}}{\color{Green}{hypotenuse}}\) as you change the size of the triangle. What do you notice?
Work out the value of \(\dfrac{\color{Red}{adjacent}}{\color{Green}{hypotenuse}}\) as you change the size of the triangle. What do you notice?
Work out the value of \(\dfrac{\color{Blue}{opposite}}{\color{Red}{adjacent}}\) as you change the size of the triangle. What do you notice?
Trigonometric ratios – sin, cos and tan
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- Worksheet (with space for student work)
- Handout (slides with exercises only; 4 per page for reduced printing)
- Skills drill worksheet (15 questions on one side of A4; answers included)
- Card sort – choosing whether to use sin, cos or tan
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- G20c – Inverse trigonometric functions
- Trigonometry assorted problems – requiring knowledge of G20a, G20b, G20c, G22a, G22b, and G23a
- A12c – Graphs of trigonometric functions