Question 1103159
{{{sqrt(4)<sqrt(7)<sqrt(9)}}}
{{{2<sqrt(7)<3}}}
7 is 3 units from 4 and 2 units from 9.
So it's 3/5 of the way from 4. 
So let's try {{{2+3/5=2.6}}}
{{{2.6*2.6=6.76=6.8}}}
So now you're in the neighborhood. 
Increase the value slightly and see how much closer you get to 7.
2.62? 
2.64?
Keep trying those values until you get as close to 7 as you like.