Topic Review — Trigonometry
This review covers all lessons in Trigonometry: the sine rule (including the ambiguous case), the cosine rule and area formula, and 2D and 3D trigonometry applications. Questions are mixed in difficulty.
Review Questions
- In triangle ABC, A = 42°, B = 67°, and a = 11 cm. Find the length of side b.
- In triangle ABC, a = 8, b = 12, and A = 38°. Find all possible values of angle B, checking both solutions for validity.
- In triangle XYZ, X = 105°, x = 20 m, and y = 9 m. Explain why there is only one possible triangle and find angle Y.
- Find the area of triangle PQR where PQ = 14 m, PR = 10 m, and angle QPR = 72°.
- In triangle ABC, the area is 30 cm², side a = 9 cm, and side b = 8 cm. Find all possible values of angle C, and for each valid case find side c.
- In triangle ABC, a = 7 cm, b = 9 cm, and C = 65°. Find side c using the cosine rule.
- In triangle ABC, a = 10, b = 7, c = 6. Find the largest angle.
- Two ships leave port at the same time. Ship A travels 24 km on a bearing of 050°. Ship B travels 18 km on a bearing of 140°. Find the distance between the two ships.
- Three towns A, B, C form a triangle. AB = 60 km, BC = 45 km, AC = 50 km. Find the angle at B (angle ABC).
- A triangular garden has sides of length 12 m, 15 m, and 20 m. Find the area of the garden using Heron’s formula or by first finding an angle.
- From the top of a 60 m cliff, the angle of depression to a boat is 28°. Find the horizontal distance from the cliff base to the boat, and the direct distance from the top of the cliff to the boat.
- A rectangular box has length 10 m, width 8 m, and height 5 m. Find the angle the space diagonal makes with the base of the box.
- A yacht sails 20 km on a bearing of 025° from port P to point A, then 15 km on a bearing of 115° from A to point B. Find the distance PB and the bearing of B from P.
- A right pyramid has a rectangular base 8 m × 6 m and a vertical height of 10 m. Find the slant height from the apex to the midpoint of the longer base edge, and the angle this slant makes with the base.
- Three surveying stations A, B, and C lie in a horizontal plane. From A, the bearing to B is 070° and the distance AB = 200 m. From A, the bearing to C is 140° and AC = 160 m. A vertical mast of height 45 m stands at B. Find the area of triangle ABC and the angle of elevation of the top of the mast from C.