## how to do probability with a dart board thats R=9in, r=5in

Standard deviation, mean, variance, z-scores, t-tests, etc.
FWT
Posts: 148
Joined: Sat Feb 28, 2009 8:53 pm

### how to do probability with a dart board thats R=9in, r=5in

how would i do probablty wit a dart board thats R=9in + r=5in. please help i cant figure this out.

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
Contact:
FWT wrote:how would i do probablty wit a dart board thats R=9in + r=5in. please help i cant figure this out.

At a guess, you're supposed to find the probability that a dart will hit some specified portion of the board...?

Find the areas of each of the regions: the whole board (using R), the inner portion (using r), and the outer ring (subtracting the second value from the first). (Use $A_R\, =\, \pi R^2$ and $A_r\, =\, \pi r^2$ to find the first two areas.)

The probability of hitting the outer or inner area will be (outer or inner area)/(total area).