Trigonometry

86.
In the diagram, B is 12 m due east of A.
C is 13 m from A and due south of B.
Right triangle ABC with B due east of A and C due south of B
Use the following information to answer the questions:
sin 1 ( 12 13 ) = 67.4 o , cos 1 ( 12 13 ) = 22.6 o , tan 1 12 13 = 42.7 o
(a) Find the length, x.
(a) ......................... m [2]
(b) Calculate angle ACB.
(b) ......................... ° [1]
(c) Find the bearing of C from A.
(c) ......................... ° [2]
Paper 2
87.
The diagram shows a right angled triangle ABC.
AC = 12 cm and angle BAC = 60°.
[sin 60 = 0.866, cos 60 = 0.5, tan 60 = 1.732]
Right triangle ABC with angle BAC = 60°
Calculate:
(a) The area of the triangle,
(a) ......................... cm2 [3]
(b) The shortest distance from B to AC.
(b) ......................... cm [3]
Paper 2
88.
Points C and G lie on horizontal line HE as illustrated in the diagram.
Lines BH and DG are vertical.
BC = 80 cm, HC = 60 cm, GE = 35 cm, DG = 40 cm, and angle DCG = 32°.
Diagram with right triangles and angles

Use any of the information in the table where necessary.
sin1 (34) = 48.6° tan32° = 0.623 cos1 (78) = 29.0°
cos1 (34) = 41.4° sin32° = 0.530 tan1 (78) = 41.2°
tan1 (34) = 36.9° cos32° = 0.848 sin1 (78) = 61.0°
(a) Calculate:
(i) The size of the angle HBC,
(a)(i) ......................... ° [1]
(ii) The length of line CD, leaving the answer as a fraction.
(a)(ii) ......................... cm [2]
(iii) Write the angle of depression of C from D.
(a)(iii) ......................... [1]
Paper 2
89.
Triangle with angles
Work out the length AC.
AC = ......................... cm [3]
Paper 2
90.
The diagram shows the right-angled triangle ABC.
D is a point on BC produced.
AB = 5 cm and BC = 12 cm.
Right triangle ABC with AB = 5 cm and BC = 12 cm
(a) Work out the length AC.
(a) AC = ......................... cm [2]
(b) Write down the value of the cosine of angle ACD.
(b) ......................... [1]
Paper 2
91.
The diagram shows a right-angled triangle ABC.
AB = 15 cm and BC = 8 cm.
Right triangle ABC with AB = 15 cm and BC = 8 cm
Calculate:
(a) the length AC,
(a) AC = ......................... cm [2]
(b) the area of triangle ABC.
(b) ......................... cm2 [2]
Paper 2
46.
In the diagram, A, B, C, and D are points on a horizontal ground.
AB = 6 m, AC = 5.6 m and CD = 4.3 m.
Angle BAC = 35° and angle ADC = 90°.
Polygon ABCD
(a) What is the name of the polygon ABCD?
......................... [1]
(b) Calculate:
(i) AD,
......................... m [2]
(ii) BC.
......................... m [2]
(c) ABPQ is a vertical wall of height 2.2 m.
The wall is built on the side AB of the polygon ABCD.
wall build on side AB

A bird walks from Q to P.
Calculate the greatest angle of elevation of the bird from C.
......................... [4]
Paper 4
47.
The diagram shows triangle PRS.
PS = 15 cm, QS = 12 cm, RS = 17 cm and Q S ^ R = 53 ° .
Triangle PRS
Calculate:
(a) QR,
......................... cm [4]
(b) The angle PSQ,
......................... [3]
(c) The shortest distance from Q to PS.
......................... cm [2]
Paper 4
48.
The diagram represents a field, ABCD in the shape of a quadrilateral.
AC is a straight footpath across the field and DC is parallel to AB.
AB = 70 m, BC = 79 m and A B ^ C = 120 ° .
Quadrilateral field
(a) Calculate the distance AC.
......................... m [4]
(b) Calculate the area of triangle ABC.
......................... m2 [2]
(c) A farmer walks the shortest distance from point B to line CD.
Calculate this distance.
......................... m [2]
Paper 4
49.
The diagram shows a quadrilateral ABCD.
AB = 4 cm, CD = 11 cm, B C ^ D = 25 ° and B A ^ D = θ .
Quadrilateral ABCD
(a) Show that B D = 16 ( 5 4 cos θ ) cm.
......................... [3]
(b) Let θ = 40°.
(i) Find the value of sin C B D .
......................... [3]
(ii) Find the value of the angle CBD.
......................... [1]
(iii) Work out the perimeter of ABCD.
......................... cm [4]
(iv) Find the area of triangle ABD.
......................... cm2 [1]
Paper 4