She used 29.8 feet of fencing for the fence -> The circumference of the circular garden is 29.8ft
Formula for circumference : 2πr
So, the radius is equal to : 29.8 : 2 : π = 4.74281730414... (round to 4.7)
Recheck : 4.7 x 2π = 29.5309709437... (close to 29.8)