Answer :
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 [tex] \sqrt{20} [/tex] can also be written as [tex] \sqrt{4} \times \sqrt{5} [/tex]. We know that the square root of 4 is 2. Thus, the square root of 20 is 2 times the square root of 5 ([tex]2 \sqrt{5} [/tex]).
We now have [tex]2 \sqrt{5} \times \sqrt{2} [/tex] 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 [tex]2 \sqrt{5 \times 2} = 2\sqrt{10} [/tex].
So [tex] \sqrt{20} [/tex] can also be written as [tex] \sqrt{4} \times \sqrt{5} [/tex]. We know that the square root of 4 is 2. Thus, the square root of 20 is 2 times the square root of 5 ([tex]2 \sqrt{5} [/tex]).
We now have [tex]2 \sqrt{5} \times \sqrt{2} [/tex] 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 [tex]2 \sqrt{5 \times 2} = 2\sqrt{10} [/tex].