IGCSE · Mathematics 0580 · Trigonometry

Sine & cosine rules: IGCSE Mathematics questions with answers

Free Sine & cosine rules questions for IGCSE Mathematics (0580), Extended tier (Supplement content), part of Trigonometry. Each question has the answer and the marking points an examiner would look for.

Generate a full Sine & Cosine Rules worksheet →All Trigonometry questions

Sine & cosine rules practice questions

Question 1Structured · 6 marksA* challenge

The diagram shows a cuboid ABCDEFGH.

ABCDEFGH15 cm5 cm12 cmNOT TO SCALE
Fig. 1.1
(a)

Calculate the length of the diagonal AG.

[3]
(b)

Calculate the angle between AG and the base ABCD.

[3]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)19.8 cm
AC2 = 152 + 52 M1
AG2 = 152 + 52 + 122 M1
19.8 A1
3
(b)37.2°
angle GAC identified B1
tan = 1215.81 or sin = 1219.85 M1
37.2 A1
3
Question 2Structured · 8 marksA* challenge

A boat sails 12 km from A to B on a bearing of 040°. It then sails 9 km from B to C on a bearing of 125°.

(a)

Show that angle ABC = 95°.

[2]
(b)

Calculate the distance AC.

[3]
(c)

Calculate the bearing on which the boat must sail to return directly from C to A.

[3]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)95°
uses co-interior / bearing of A from B = 220 M1
220 − 125 = 95 A1
2
(b)15.6 km
cosine rule M1
AC² = 12² + 9² − 2 × 12 × 9 × cos 95° M1
15.6 km A1
3
(c)255°
sine rule for angle BAC M1
angle BAC = 35.0° A1
255° A1
3
Question 3Structured · 3 marks

The diagram shows triangle ABC.

40°63°ABC17 cmNOT TO SCALE
Fig. 3.1

Calculate the length of AC.

[3]
Show answers and mark scheme
PartAnswer and marking pointsMarks
23.6 cm
ACsin 63 = 17sin 40 M2
M1 for a correct implicit sine rule
23.6 A1
3
Question 4Structured · 10 marksA* challenge

In triangle ABC, AB = 15 cm, AC = 14 cm and angle BAC = 108°.

108°ABC15 cm14 cmNOT TO SCALE
Fig. 4.1
(a)

Calculate BC.

[3]
(b)

Calculate angle ABC.

[3]
(c)

Calculate the shortest distance from C to the line AB.

[2]
(d)

Calculate the area of triangle ABC.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)23.5 cm
BC2 = 142 + 152 − 2 × 14 × 15 × cos 108 M2
23.5 A1
3
(b)34.6°
sin B14 = sin 10823.47 M2
34.6 A1
3
(c)13.3 cm
14 sin 108 M1
13.3 A1
2
(d)99.9 cm²
½ × 14 × 15 × sin 108 M1
99.9 A1
2
Question 5Structured · 8 marksA* challenge

A boat sails 18 km from A to B on a bearing of 050°. It then sails 8 km from B to C on a bearing of 125°.

(a)

Show that angle ABC = 105°.

[2]
(b)

Calculate the distance AC.

[3]
(c)

Calculate the bearing on which the boat must sail to return directly from C to A.

[3]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)105°
uses co-interior / bearing of A from B = 230 M1
230 − 125 = 105 A1
2
(b)21.5 km
cosine rule M1
AC² = 18² + 8² − 2 × 18 × 8 × cos 105° M1
21.5 km A1
3
(c)251°
sine rule for angle BAC M1
angle BAC = 21.1° A1
251° A1
3
Question 6Structured · 10 marksA* challenge

In triangle ABC, AB = 13 cm, AC = 8 cm and angle BAC = 62°.

62°ABC13 cm8 cmNOT TO SCALE
Fig. 6.1
(a)

Calculate BC.

[3]
(b)

Calculate angle ABC.

[3]
(c)

Calculate the shortest distance from C to the line AB.

[2]
(d)

Calculate the area of triangle ABC.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)11.6 cm
BC2 = 82 + 132 − 2 × 8 × 13 × cos 62 M2
11.6 A1
3
(b)37.4°
sin B8 = sin 6211.63 M2
37.4 A1
3
(c)7.06 cm
8 sin 62 M1
7.06 A1
2
(d)45.9 cm²
½ × 8 × 13 × sin 62 M1
45.9 A1
2

More Trigonometry questions

Want a mentor, not just a paper?

Riyaz Shaikh has mentored IGCSE, IB and A Level students for 15+ years, one-on-one, online and in Mumbai. The hardest questions on this site are the ones he uses to find a student's weak points.

Meet Riyaz →

Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in