Topics
7. Trigonometry
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AustraliaQLD
Year 12

7.03 The cosine rule

Lesson
Worksheet
Practice

Interactive practice questions

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

Round your answer to two decimal places.

A triangle with its vertices labeled as A, B, and C. The angle at vertex A measures $33^\circ$33°. The side opposite to the $33^\circ$33° angle, side $BC$BC, is labeled $a$a units, indicating its unknown length. Side $AB$AB measures $30$30 units, as shown by the scale line beneath it. Side $AC$AC measures $13$13 units. Side $AB$AB and Side $AC$AC are adjacent to the $33^\circ$33° angle at vertex A.
Easy
3min

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

Round your answer to two decimal places.

Easy
2min

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

Round your answer to two decimal places.

Easy
2min

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

Round your answer to two decimal places.

Easy
2min
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Outcomes

4.2.1.3

establish and use the sine (ambiguous case is required) and cosine rules and the formula 𝐴rea=1/2 bc sin𝐴 for the area of a triangle

4.2.1.4

construct mathematical models using the sine and cosine rules in two- and three-dimensional contexts (including bearings in two-dimensional context) and use the model to solve problems; verify and evaluate the usefulness of the model using qualitative statements and quantitative analysis

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