Question

Calculate the area of a circle with a radius of 2 cm and a circle with a radius of 4 cm. leave your answers in terms of pi. when the radius doubles, does the area of the circle double?

a. 4π cm2; 8π cm2; no
b. 4π cm2; 16π cm2; no
c. 4π cm2; 16π cm2; yes
d. 4π cm2; 8π cm2; yes

Answer 1

Area of the circle with radius 2:
A = pi * radius^2
= pi * 2^2
= pi *4
= 4pi cm^2
Area of the circle with radius 4:
A = pi * 4^2
= pi * 16
= 16pi cm^2

16 is not 4*2 so no the statement is incorrect
B is the correct option