The number, whose square is equal to the difference of the squares of 75.15 and 60.12, is = ?

$$\eqalign{ & {\text{Let the number be = }}x \cr & {\text{According to question,}} \cr & {x^2} = {\left( {75.15} \right)^2} - {\left( {60.12} \right)^2} \cr & \Rightarrow {x^2} = {\left( {75.15 + 60.12} \right)}\,{\left( {75.15 - 60.12} \right)} \cr & \Rightarrow {x^2} = 135.27 \times 15.03 \cr & \Rightarrow {x^2} = 2033.1081 \cr & \Rightarrow x = 45.09 \cr} $$