Sine, cosine rules for Edexcel GCSE Maths

Sine, cosine rules

This page covers the following topics:

1. Sine rule
2. Problems with sine rule
3. Cosine rule
4. Problems with cosine rule

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Sine rule

When solving word problems with the sine rule it is best to draw a picture and label the known angles/side lengths.

Problems with sine rule

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Cosine rule

When solving word problems with the cosine rule it is best to draw a picture and label the known angles/side lengths.

Problems with cosine rule

1

Use the cosine rule to find angle A, given a = 5, b = 7 and c = 6.

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44.4º

Use the cosine rule to find angle A, given a = 5, b = 7 and c = 6.

2

Find the length of pole A. Give your answer with two decimal places.

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12.45 m

Find the length of pole A. Give your answer with two decimal places.

3

The diagram shows a ladder propped against a slightly slanted wall. Find the angle between the ladder and the wall.

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27.7º

The diagram shows a ladder propped against a slightly slanted wall. Find the angle between the ladder and the wall.

4

A triangle is created using 3 poles. The poles are 20 m, 25 m and 23 m in length. Find the angle between the 20 m and 23 m poles.

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70.7º

A triangle is created using 3 poles. The poles are 20 m, 25 m and 23 m in length. Find the angle between the 20 m and 23 m poles.

5

Two match sticks are held up with their tips against each other. Both match sticks are 5 cm long. The angle between them is 65º. Find the distance between the bottom of the match sticks along the ground.

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5.37 cm

Two match sticks are held up with their tips against each other. Both match sticks are 5 cm long. The angle between them is 65º. Find the distance between the bottom of the match sticks along the ground.

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