Find the odd number / letters / word from the given alternative:

[amp_mcq option1=”28″ option2=”45″ option3=”72″ option4=”81″ correct=”option1″]

The odd number in the given set is 45.

All other numbers are perfect squares.

A perfect square is a number that can be obtained by squaring an integer.

28 = 7^2

72 = 8^2

81 = 9^2