Metal for reward!
A TV station’s weather radar can detect precipitation in a circular region having a diameter of 100 mi. Find the area of the region.
a.

31,400 mi2

c.

15,700 mi2
b.

7,850 mi2

d.

3,140 mi2

Question

Metal for reward!
A TV station’s weather radar can detect precipitation in a circular region having a diameter of 100 mi.  Find the area of the region.
a.
	
31,400 mi2
	
c.
	
15,700 mi2
b.
	
7,850 mi2
	
d.
	
3,140 mi2

austinl · Answer

$$A=\pi\times r^2$$

anonymous · Answer

it doesn't come out right

anonymous · Answer

$$r = \frac{1}{2}d$$

anonymous · Answer

Wait, do you have a picture of the problem?  None of these answers would be correct.

anonymous · Answer

no, i don't

anonymous · Answer

Oh I get it now.  First find what the radius is $\left(r = \frac{1}{2}d\right)$, then plug it into the area formula $\left(A=\pi r^2\right)$.

Then, they want you to approximate $\pi$ as 3.14 and multiply out your area.  Then choose the closest answer.

anonymous · Answer

yes, what would it be?

anonymous · Answer

Well, how far can you get on your own?

anonymous · Answer

iI got 200 because I don't know how to solve for the given price

anonymous · Answer

No, the $diameter$ is 100.  The radius is one-half the diameter.  So, what's the radius?