Question

P is in the shape of a circle. Q is in the shape of a quarter circle of radius 20 cm. P Q 20 cm The area of Q is 4 times the area of P. Work out the radius of P. You must show all your working.

Answer 1

(1) Find area of Q:
a = pi (r^2)
= pi (20^2)
= pi (20cm)(20cm)
= 400cm^2

(2) Find area of P:
400/4 = 100cm^2

(3) Find radius of P:
100cm^2/pi = pir^2/pi
sq. root of 100 = sq. root of r^2
r = 10 cm


Answers;
radius (Q) = 20cm
area (Q) = 400cm^2

radius (P) = 10cm
area (P) = 100cm^2