Question

What of the following do we have to add with 280 to make it a perfect square nearest to it?

• A. $3$
• B. $3^2$
• C. $2^2$
• D. $1$

Answer 1

The correct option is B $3^2$

$100<280<400$
${10}^2<280<{20}^2$
So, square closest to 280 will lie between 10 and 20.

Number	Square
11	121
12	144
13	169
14	196
15	225
16	256
17	289
18	324
19	361

The smallest perfect square greater than 280 is 289.
So, the number to be added is:
$289-280=9=3^2$