maths problem!

[Jules6]

A ball with a diameter of 40cm is lying tight to a wall, which is perpendicular to the ground. What is the largest diameter ball, which can fit through the gap between the wall/ground and the 40cm ball?

[coggles]

8cm (although i am sure someone will correct me...!!!)

[coggles]

What quiz are you trying to do?

[shybearuk]

Jules, in the future, if you have multiple questions, could you please put them all into one? The 'recently asked questions' only allows a certain amount of questions on view at any one time, and by putting several on at once, you push an equal amount off of the page. Once questions are lost off of the page it can be very tricky to find them again. Not nagging, just a request. :)

[bernardo]

6.8629 cm. This is from the equation r(1+root2)=20(root2-1) which means r = 20(root2-1)/(1+root2) which gives r = 3.4315 which means d=2r = 6.8629.

[coggles]

I stand corrected! I wasn't that far out though..........

[Jules6]

Thanks for the answer, Im doing the Macmillan quiz, and sorry about using up too much space - haven't used this site before, and got a little carried away :-(