Question

.

The diameter of the larger circle is 20.4 cm.
The diameter of the smaller circle is 10.8 cm.

What is the approximate area of the shaded region?



A.
326.7 cm²

B.
289.4 cm²

C.
235.1 cm²

D.
72.3 cm²s

Answer 1

I can't see your diagram, but I'm assuming that the smaller circle is in the bigger circle and they want you to find the area in the bigger circle not taken up by the smaller circle so

find the areas
pi times radius^2
diameter=2r
dimeter/2=radius
larger=20.4=d
20.4/2=r=10.2
pi =aprox 3.14
3.14 times 10.2^2=326.686=area of larger


smaller 10.8=diameter
10.8/2=5.4
3.14 times 5.4^2=91.5624

subtract

326.686-91.5624=235.123

round to 1 decimal place
235.1 cm^2
the answer is C

Answer 2

assuming the shaded area is the area of the larger circle minus the area of the smaller circle:
radius of larger circle = 10.2
radius of the smaller circle = 5.4

pi*(10.2)^2 - pi*(5.4)^2 = 235.242

therefore your answer should be C: 235.1