# Thread: pls help!!!!!

1. ## 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....

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.

PLS HELP ME I HAVE NO IDEA HOW TO DO THIS!!!!!!

2. 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 $\displaystyle \pi 2^2=4\pi$. And the total area which is your big circle has diameter of 8 thus, radius of 4 thus, area of $\displaystyle \pi 4^2=16\pi$ Now divide them thus,$\displaystyle \frac{4\pi}{16\pi}=\frac{1}{4}$. 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?