Estimate the value of the square root of 122 to the nearest interger

Hello,
without any calculator:
Let's x the square root of 122

121<x²<144 ==>11²<x²<12²
==>11<x<12
as 11.5²=11.5*11.5=132.25 ==>11<x<11.5
x is near 11 than from 12
Answer= 11.

The answer is c because you turn 17.5% into a decimal which gives you .175 then you times that by $361.35 which gives you 63.23625 but then you round that which gives you 63.24. then you at 63.24 pulse 361.35 and you round it which gives you $425