The radius of the circle is 1km
Attach an image of the line on a Cartesian plane for us to help you
Area = L*W
Original Area = 12*14 = 168
Multiply the dimensions by 2 = 12*2 = 24 and 14*2 = 28
New Area = 24 *28 = 672
New Area divided by original area = 672/168 = 4
The garden will be 4 times bigger in area
Area or a circle
A= 3.14 (pi) multiplied by the radius to the second power
So if a circles radius is 3 cm it would be pi multiplied by 9 which equals 28.27 cm2
Circumference
C= pi multiplied by the diameter