Question

Which of the following numbers is not a perfect square?

a. 49
b. 121
c. 125
d. 144

Answer 1

C. 125

Explanation:

source: trust me bro

Answer 2

C. 125

Explanation:

49 = 7×7 ← a perfect square

121 = 11×11 ← a perfect square

144 = 12×12 ← a perfect square

but:

125 = 5×5×5 = 5√5×5√5 and 5√5 is not integer so 125 is not a perfect square