I know the radius of the whole dart board, but it asks to find the radius of the inner most circle inside the dart board. How can I find it?

Question

ganeshie8 · Answer

wat other info it gives ?

anonymous · Answer

there were 350 holes in the dart board that seemed evenly spaced. of these, 5 were within circle 9(the most inner circle). the radius of the whole board is 8 inches. it asks to find a good estimate for the radius of circle 9.

anonymous · Answer

is this enough information? it's all the problem states

ganeshie8 · Answer

yes it is enough, one sec..

ganeshie8 · Answer

Since there are 5 holes in the inner circle,
and 350 holes in the bigger circle, ratio of areas would be :-

$\large  \frac{5}{350} =  \frac{1}{70}$

ganeshie8 · Answer

that gives, ratio of radii =
$\large \sqrt{\frac{1}{70}}$

ganeshie8 · Answer

Multiply it wid the bigger radius

anonymous · Answer

thank you so much!

ganeshie8 · Answer

np :)