calculus-geometry profile image 86

The smaller gray circles inscribed within the larger circle have equal sizes.

They are all tangent to one another as well as to the larger circle. If the smaller circles each have a radius of 20, what is the radius of the larger circle?

sort by best latest

bubba-math profile image61

Best Answer Jim Bob (bubba-math) says

4 years ago
 |  Comment
ib radmasters profile image61

ib radmasters says

4 years ago
 |  Comment
tussin profile image59

I'M BANNED Y'ALL!!!!!!!!!! (tussin) says

4 years ago
 |  Comment
  • bubba-math profile image

    Jim Bob (bubba-math) 4 years ago

    Descartes' Theorem. That's a much faster way to solve it for sure.

profile image0

Larry Wall says

4 years ago
 |  Comment
  • profile image

    Larry Wall 4 years ago

    I accept the answer, I just wish you would tell me where I was wrong in my approach. I still contend that the smaller circles had no impact on the radius of the larger circle. Would the radius be different if the smaller circles were not there?

  • See all 3 comments
normal profile image59

normal says

4 years ago
 |  Comment
  • calculus-geometry profile image

    TR Smith (calculus-geometry) 4 years ago

    You're on the right track. You do need to examine what's going on in the center of the circle and at the points of tangency.