Question 512615
Yes, he does have enough fencing. 
We're talking perimeter, and if the garden is 4ft. X 7ft, we're just doubling the numbers and adding them. 8+14=22ft, which is the perimeter of this garden.
Now remember, the problem said 10YDS. of fence, so we have to transalate that to feet. 
There are 3 feet in a yard, so 10yds. X3=30ft. of fencing. 
He has 30ft. and a 22ft perimeter garden, thus he has more than enough to surround the garden! 

Hope I helped! :)
(Also, I'm not a great speller, I apologize for any errors.)
-Rosey