In the diagram, PQS is a right angled triangle, ∠PSQ = 90o, |PS| = 3 cm, |PQ| = 5 cm, ∠PRS = 61o and ∠QPR = xo. Calculate, correct to one decimal place, the
This question was reportedly attempted by majority of the candidates and they performed well in it. However, it was also observed that a few of them applied the wrong trig. ratio.
In part(a) ∠QPS = cos-1 = 53.13o. xo = 53.13o – (90o – 61o) = 24.1o
In part(b), QS = = 4 cm. Area of PQS = x 3 x 4 = 6 cm2
|RS| = 3tan29o = 1.6629. Area of PRS = x 3 x 1.6629 = 2.49439
Area of PQR = Area of PQS – Area of PRS = 6 – 2.49439 = 3.5 cm2, correct to 1 decimal place.
Q
R
o 61o
P 3 cm S
PQS is a right angled triangle, ∠PSQ = 90o, |PS| = 3 cm, |PQ| = 5 cm, ∠PRS = 61o and ∠QPR = xo. Calculate, correct to one decimal place, the 
PQR. 
= 53.13o. xo = 53.13o – (90o – 61o) = 24.1o
= 4 cm. Area of 
PQS = 
x 3 x 4 = 6 cm2
PRS = 
x 3 x 1.6629 = 2.49439
PQR = Area of 
PQS – Area of 
PRS = 6 – 2.49439 = 3.5 cm2, correct to 1 decimal place.