G1. √49
7
This is a perfect square. Essentially what this means that two of the same numbers (In this case 7 and 7) are multiplied together to get the number under the radical.
G2.

=

Take the square root of the top which will be 1
Then take the square root of the denominator which will be 2
Both the numerator and denominator are perfect squares.
2*2 = 4
1*1 = 1

G3.

=

Take the square root of the top which will be 6
Take the square root of the bottom which will be 7
Again, both numerator and denominators are perfect squares
6*6 = 36
7*7 = 49

Hope this helped!
~Just a girl in love with Shawn Mendes