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 \(\pi = \frac{22}{7}\)]
-
4.19cm2
- 8.38cm2
- 10.5cm2
- 20.9cm2
The correct answer is: A
Explanation
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