4. Trigonometric Ratios

4.01 Review of trigonometry for right-angled triangles

4.02 Angles of inclination

4.03 The sine rule

4.04 The cosine rule

4.05 Further problem solving with trigonometry

4.06 Area of a non-right-angled triangle

Year 11

4.04 The cosine rule

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

Outcomes

ACMMM031

establish and use the sine and cosine rules and the formula Area=1/2 bc sin⁡A for the area of a triangle

What is Mathspace

About Mathspace