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Prerequisites

- G20b – Trigonometric ratios – sin, cos and tan
- G20c – Inverse trigonometric functions
- G22a – The sine rule – knowledge of the convention to label sides and opposite angles a, b,c, and A, B and C respectively is required for this whole lesson, and knowledge of the sine rule itself is required for the Gamma exercise
- G22b – The cosine rule – knowledge of the cosine rule is required for the Gamma exercise

# Area of a triangle using sine

Teacher resources

Links to past exam questions

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Unlimited practice questions

## Activity: areas of regular polygons and limits

This applet shows you a regular polygon. Drag the slider to change its number of sides. No matter how many sides it has, the distance from its centre to each vertex is fixed at 1 cm. What do you notice about the area of the polygon as you increase the number of sides it has?

What next?

- Trigonometry assorted problems – requiring knowledge of G20a, G20b, G20c, G22a, G22b, and G23a
- G23b – Mixed problems using trigonometric formulas