Answer:

Step-by-step explanation:


Easily, take the square root of the number in the right side to find the radius

is the answer
I am not sure if I am right, but this is the best I can answer.
Useing reason, and logic, my guess would be if you take 125, and divided it by 4, you would get 31.25. that should be the answer... if i am wrong, i am truely sorry. I havent been in the subject in a while...
Hope this helps.
Answer :
2/9v-2/5v=5-4
-8/45v=1
v= -45/8