Question
Find the square roots of the following number by the prime factorisation method.
400
400
✓
Answer
Given number is 400.
Using prime factorisation, we get
$\begin{aligned} 400 & =2 \times 2 \times 2 \times 2 \times 5 \times 5 \\ & =(2 \times 2 \times 5)^2 \\ \therefore \sqrt{400} & =2 \times 2 \times 5=20\end{aligned}$
Hence, the square root of 400 is 20.
Using prime factorisation, we get
$\begin{aligned} 400 & =2 \times 2 \times 2 \times 2 \times 5 \times 5 \\ & =(2 \times 2 \times 5)^2 \\ \therefore \sqrt{400} & =2 \times 2 \times 5=20\end{aligned}$
Hence, the square root of 400 is 20.
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