ITMC 2026 Grade 4 National Preliminary sample-r1 Question 8

A square number is the product of a positive integer with itself: $1\times1=1,2\times2=4,3\times3=9,4\times4=16,5\times5=25,\ldots $. Thus 1, 4, 9, 16, 25, …are square numbers. What is the greatest three-digit square number less than 400?