20,000 x 25 = 500,000
500,000 divided by 100 = 5,000 members are lost.
Members left = 15,000
Members added = 10,000
Members every year = Members left + Members added
= 15,000 + 10,000
= 25,000
I’m not sure what you are trying to say in this problem?
The formula for the radius is

so the answer would be 6 inches
You can arrange it any way as long as you keep the 2 as the very first number