Question 1179548
<br>
{{{28*x*y*65 = (2*2*7)*x*y*(5*13)}}}<br>
If that product is to be a perfect square, we need other prime factors of 5, 7, and 13.<br>
5*7=35 is between 28 and 65; but that leaves us with the unused prime factor of 13.<br>
But 13*4=52, and 52 is also between 28 and 65; and adding the additional factor of 4 keeps the product a perfect square.<br>
ANSWER: 28, 35, 52, 65<br>