I would first suggest you to find the square root of 20. This means that you need to find two factors, one of which needs to be a perfect square. Seems like 4 x 5 can work because 4 is a perfect square.
So \(\sqrt{20}\) can also be written as \(\sqrt{4} \times \sqrt{5}\). We know that the square root of 4 is 2. Thus, the square root of 20 is 2 times the square root of 5 (\(2 \sqrt{5}\)).
We now have \(2 \sqrt{5} \times \sqrt{2}\) and since 2 is not a perfect square we cannot really simplify it any further. Therefore, we just multiply the square root of 5 and the square root of 2 because they are under the radical sign. So we get \(2 \sqrt{5 \times 2} = 2\sqrt{10}\).
