PQR is a sector of a circle centre O, radius 4cm. If PQR = 30o, find, correct to 3 significant figures, the area of sector PQR. [Take \(\pi = \frac{22}{7}\)]
A
4.19cm2
B
8.38cm2
C
10.5cm2
D
20.9cm2
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Given q2 = 25 - r2.....(1)
from pythagora's theorem
P2 = q2 + r2.......(2)
put (1) into (2)
p2 = 25 - p2 + x2
p2 = 25
p = \(\sqrt{25}\)
= 5
Source: Myschool Past Questions Archive (Record #36358)