What is the square root of 0.09 ?

Which smallest number must be added to 2203 so that we get a perfect square? 

If the sum and difference of two number are 20 and 8 respectively, then the difference of their squares is: 

$$3\sqrt{ {72.9\over0.4096}}$$ is equal to : 

Direction : What should come in place of the question (?) in the following question.

140% of 450 + 24% of 650 =?

The number, whose square is equal to the difference between the squares of 975 and 585, is: 

(5.5)³-(4.5)³ is equal to :