Mastering Sine & Cosine Rules

Mathematics
Year 9
12 questions
~24 mins
0 views0 downloads

About This Worksheet

A worksheet covering Sine & Cosine Rules for Year 9 students to develop understanding and application skills.

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Full preview • 12 questions

Mastering Sine & Cosine Rules

Subject: MathematicsGrade: Year 9
Name:
Date:

Untitled Worksheet

Grade Year 9
A

Practice Questions

Answer all questions. Show your working in the grid spaces provided.
1.
In triangle ABC, side AB = 8 cm, side AC = 6 cm, and angle BAC = 60°. Calculate the length of side BC using the Law of Cosines.
[3 marks]
2.
In triangle PQR, side PQ = 7 cm, side PR = 9 cm, and angle PQR = 45°. Find the length of side QR using the Law of Cosines.
[3 marks]
3.
In triangle XYZ, side XY = 5 cm, side XZ = 7 cm, and angle XYZ = 120°. Calculate side YZ.
[3 marks]
4.
In triangle DEF, side DE = 10 cm, side DF = 13 cm, and angle DFE = 70°. Find side EF using the Law of Cosines.
[3 marks]
5.
Calculate the length of side XY in triangle PQR where sides PQ = 6 cm, PR = 8 cm, and angle PQR = 30° using the Law of Cosines.
[3 marks]
6.
In triangle GHI, side GH = 9 cm, side GI = 12 cm, and angle GHI = 45°. Find side HI.
[3 marks]
7.
In triangle JKL, side JK = 4 cm, side JL = 6 cm, and angle JKL = 100°. Calculate side KL.
[3 marks]
8.
Using the Law of Cosines, find the angle opposite side AB in a triangle with sides AB = 8 cm, AC = 6 cm, and BC = 10 cm.
[3 marks]
9.
In triangle MNO, sides MN = 7 cm, MO = 9 cm, and NO = 10 cm. Find angle NMO.
[3 marks]
10.
In triangle QRS, side QR = 8 cm, side QS = 15 cm, and angle QRS = 60°. Calculate side RS.
[3 marks]
11.
A boat is sailing from point A to point B, 10 km apart. The boat's course makes an angle of 40° with the shoreline. How far is the boat from point A when it is directly opposite point B, assuming it follows the Law of Cosines?
[4 marks]
12.
A surveyor measures two sides of a triangular plot as 50 m and 80 m, with the included angle of 60°. Find the third side of the plot.
[4 marks]

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Details

Created
12/30/2025
Updated
12/30/2025
Type
worksheet