The magnitude of a vector is the square root of the sum of the squares of its coordinates:
[tex]||(a,b)|| = \sqrt{a^2+b^2}[/tex]
So, for example, the first vector has magnitude
[tex]||(2,1)|| = \sqrt{2^2+1^2}=\sqrt{4+1}=\sqrt{5}[/tex]
The second vector has magnitude
[tex]||(0,1)||=\sqrt{0^2+1^2}=\sqrt{0+1}=1[/tex]
You can go on like this with all the other cases
