Q3 of 85 Page 133

Find the smallest number by which 2400 is to be multiplied to get a perfect square and also find the square root of the resulting number.

Given, a number as 2400. We need to find out a number which if multiplied by the given number we should get a perfect square.

To find out square root of the resulting number


Step 1: Resolve 2400 into prime factors



We get, 3 × 2 × 5 × 2 × 5 × 2 × 2 × 2


Step 2: Pair the factors obtained


(2 × 2) × (5 × 5) × (2 × 2) × 3 × 2


Step 3: multiply the number with the factor which is alone.


Here, 2,5 are in pairs and 3,2 are alone.


So, we must multiply the given number by 3 × 2 to get a perfect square.


2400 × 3 × 2 = 2400 × 6 = 14400.


Step 4: The resulting number obtained is 14400



Square root is found out using common factors


= )


= 5 × 2 × 3 × 2 × 2


= 120


Hence, 6 should be multiplied to the given number “2400” to make it perfect square. The square root of the resulting number is 120.


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