Question

MEDALS AND FAN

1 Find the exact area of a circle having the given circumference.

4(3)

A =

2√3
4√3
12

2 Find the exact area of the region bounded by two concentric circles with radii 10 inches and 6 inches.

16
64
88

3 Find the area of a circle whose area equals the half of the sum of the areas of two circles with radii 2 and 3.

13
6.5
5

Answer 1

One question Per post I will do #1
1. Find the exact area of a circle having the given circumference.

4(3)
A =
A. 2√3
B. 4√3
C. 12

Circumference = 2r(pi) = 4(sqrt3pi)
r(pi) = 2(sqrt3pi)
r = 2(sqrt3pi)/pi

Now we can find area
------------------
area = pi(r^2)
= pi(2(sqrt3pi)/pi)^2
= pi(12pi/pi^2)
= 12pi^2/pi^2

So the answer is C. 12