I worked the problem and I worked the problem.

I worked 7 full sheets of paper. Combining all the math I learned throughout my entire math career. 1.5 hours later I wasn’t done and so I took a break and went to a chem. review session. I came back, reviewed my thoughts and equations and realized I could solve it much more easily. I reviewed my thoughts and equations some more and realized I could solve it in one step.

The answer is R*sqrt(6)/2 or .225R.