SOLUTION OF TRIANGLES
PAPER 2
1. Diagram 1 shows a quadrilateral ABCD such that ABC is acute.
D 5.2 cm
C
9.8 cm 12.3 cm
9.5 cm
40.5
A
DIAGRAM 1
(a) Calculate
(i) ABC
(ii) ADC
(iii) the area , in cm 2 , of quadrilateral ABCD. [8 marks]
(b) A triangle A' B 'C ' has the same measurements as those given for triangle ABC,
i.e., A'C ' =12.3 cm, C ' B ' = 9.5 cm, dan B ' A'C ' = 40.5 , but which is
different in shape to triangle ABC .
(i) Sketch the triangle A' B 'C ' ,
(ii) State the size of A' B 'C ' [2
marks]
2. Diagram 2 shows a triangle ABC.
A
20 cm
65
B
15 cm
DIAGRAM 2
(a) Calculate the length of AC. [2 marks]
1
(b) A quadrilateral ABCD is now formed so that AC is the diagonal, ACD = 40
and AD = 16 cm.
Calculate the two possible values of ADC. [2 marks]
(c) Using the acute ADC in (b), calculate
(i) the length of CD
(ii) the area of the quadrilateral ABCD . [6 marks]
3.
S
R
7.0 cm
5.5 cm
50 48
Q
P
DIAGRAM 3
Diagram 3 shows SPR and QPR where PR = 5.5 cm, SP = 7.0 cm, RPQ = 50
and RQP = 48 . Given that the area of PQR is twice the area of PSR,
calculate
(a) the length of PQ [3 marks]
(b) the area of PSR [3 marks]
(c) the length of SR [4 marks]
2
4. In diagram 4 , AB= 13 cm , BC= 7 cm , AG = 6 cm , GE = 24 cm, FE = x cm ,
BAG 60o and DFE 90o . Calculate
(a) the length of CE, [3 marks]
(b) CEA , [3
marks]
(c) the value of x if the area of DFE is equal to the area of BAG . [4 marks]
C
7 cm
B D
13 cm
60o
A E
6 cm G F x cm
24 cm
DIAGRAM 4
5. Diagram 5 shows a quadrilateral ABCD.
D
5 cm
C
40o
6 cm
B
9 cm
A
DIAGRAM 5
The area of triangle BCD is 13 cm2 and BCD is acute.
Calculate
(a) BCD, [2 marks]
(b) the length , in cm , of BD, [2 marks]
(c) ABD, [3 marks]
(d) the area , in cm 2 , of quadrilateral ABCD . [3 marks]
3
ANSWER – SOLUTIONS OF TRIANGLES
1. (a) (i) 57.23 or 57 14'
(ii) 106 4 '
(iii) 82.38 cm 2
(b) (i)
C'
A' B' B
(ii) 122.77 or 122 46 '
2. (a) 19.27 cm
(b) 50 73' or 50 44' , 129.27 or 129 16 '
(c) (i) 24.89 cm
(ii) 290.1 cm 2
3. (a) 7.329 cm
(b) 7.720 cm 2
(c) 2.952 cm
4. (a) 26.46 cm
(b) 40.89o or 40o53'
(c) x = 8.832
5. (a) 60o 4'
(b) 5.574 cm
(c) 116o 32'
4
(d) 35.44 cm 2