Find the number whose square is equal to the difference

Find the number whose square is equal to the difference between the square of 75.15 and 60.12. ?

Let the number be x.
Then, accordingto the question,
x² = (75.15)² - (60.12)²
⇒ x² = 5647.52 - 3614.41
⇒ x² = 2033.11
∴ x = 45.09