If \({1 \over {10}}:{1 \over a} = {1 \over a}:{1 \over 1},\)then value of a is
1
\(\sqrt 5\)
2
\(\sqrt {10}\)
3
\(2\sqrt 3\)
4
5
5
10
If \({1 \over {10}}:{1 \over a} = {1 \over a}:{1 \over 1},\)then value of a is
\(\sqrt 5\)
\(\sqrt {10}\)
\(2\sqrt 3\)
5
10