8 times 2pie r> = (x+y) *15 > =7 times 2πr
10 times 2pie r> = (x+y+6) *15 > =9 times 2πr
You can get it by adding 90 at the same time.
8 times 2pie r+90 > =(X+Y+6)* 15 & gt； =7 times 2 Pie R+90
Meet the following formula, then
8 times 2pie r+90 > =9 times 2 pie r and 10 times 2 pie R & gt=7 times 2 pie R+90.
The result is 9.5.
Therefore, the minimum diameter is10m, and the maximum diameter is 28m.