75² = ?

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 75²,

7 is the number before 5, one plus the number is 8.

So, 7 x 8 = 56

75² = 56_ _

Add 25 at the end gives 5625.

∴ 75² = 5625