# pls help!!!!!

• Jan 9th 2006, 06:36 PM
pianogurl1250
pls help!!!!!
i have a question about probabilty.heres the ? theres a dartboard and the diameter is 8 in but the inner shaded circle is 4in.an it says that if i through 20 darts at it how many will land inside the shaded circle.... :eek:

theres also another one thats like this:if i drew a triangle(4ft by 1ft) on the white board(5ft by 3ft) whats the probabilty thats id hit inside the triangle if i was throwin something at it. :confused:

PLS HELP ME I HAVE NO IDEA HOW TO DO THIS!!!!!!
• Jan 9th 2006, 06:45 PM
ThePerfectHacker
In these types of problems, you divide the area that you want to get by the area that is whole. Since the smaller circle has diameter of 4 its radius is 2 thus its area is $\pi 2^2=4\pi$. And the total area which is your big circle has diameter of 8 thus, radius of 4 thus, area of $\pi 4^2=16\pi$ Now divide them thus, $\frac{4\pi}{16\pi}=\frac{1}{4}$. Thus probability is 25%. Since you are throwing 20 darts 20% of them should hit the region thus 20% of 20 = 5.

Do you want to try the second one by yourself?