Topics
8. Trigonometry
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AustraliaAU
Year 11

8.04 Cosine rule

Lesson
Worksheet
Practice

Interactive practice questions

To use the cosine rule to find the length of $AC$AC, which angle would need to be given?

 

A triangle with its vertices labeled A, B, and C. Side BA has a length of 31.05 cm and side BC has a length of 38.44 cm. Side AC, which is opposite to the angle at vertex B, $\angle ABC$∠ABC or $\angle CBA$∠CBA, is not labeled. 

$\angle CAB$∠CAB

A

$\angle BCA$∠BCA

B

$\angle ABC$∠ABC

C
Easy
< 1min

Which of the following is true for the given triangle?

Easy
< 1min

Which of the following is the correct equation to solve for missing side $a$a?

Easy
< 1min

Find the length of $a$a using the cosine rule.

Round your answer to two decimal places.

Easy
3min
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Outcomes

ACMGM036

solve problems involving non-right-angled triangles using the sine rule (ambiguous case excluded) and the cosine rule

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