Answer:
<em><u>To find the biggest 4-digit number which is a perfect square, we have to take the square of biggest 2-digit number. ∴ The biggest 4-digit number which is a perfect square = 9801.</u></em>
Step-by-step explanation:
9801
well we know 100 squared is the first 5 digit square number so it must be 99 squared, which is 9801