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Mathematical Methods ยท Unit 4 ยท Trigonometry ยท Cosine and sine rules

Use the sine rule (ambiguous case is required), ๐‘Ž sin(๐ด) = ๐‘ sin(๐ต) = ๐‘ sin(๐ถ), where ๐‘Ž, ๐‘ and ๐‘ are the side lengths of the triangle and ๐ด, ๐ต and ๐ถ are the corresponding opposite angles.

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Question 1

In triangle ABC, angle A is 35ยฐ, side b is 12 cm and side a is 8 cm. (a) Use the sine rule to calculate the size of angle B, correct to the nearest degree. (2 marks) (b) Explain whether a second possible value for angle B exists for this triangle. (2 marks)

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Question 2

Identify the possible values for angle R in the triangle shown.

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Question 3

A triangle has sides of length 7 cm and 9 cm, with an angle of 35ยฐ opposite the 7 cm side. Use the sine rule to find the angle opposite the 9 cm side, correct to the nearest degree. State both possible values.

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Question 4

In triangle ABC, \(a = 8\) cm, \(b = 12\) cm and \(\angle A = 35^\circ\). Explain why two different triangles can be constructed with these measurements.

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