I'm sorry but I'm not into square roots yet :(
Answer:
502
Step-by-step explanation
108 has the numbers 0, 1, and 8 which added together totals 9
603 has the numbers 0, 3, and 6 which added together totals 9
360 has the numbers 0, 3, and 6 which added together totals 9
502 has the numbers 0, 2, and 5 which equal 7
502 is the odd one out
Just do the slope of 5/3×