225 ² =?

To find a square number ending with 5, we multiply the number before 5 with one plus the number and add 25 at the end.

Now, in 225²,

22 is the number before 5, one plus the number is 23.

So, 22 x 23 = 506

225² = 506_ _

Add 25 at the end gives 50625.

∴ 225² = 50625