3 miles, because if you think of it like a box, a box has to have 4 sides, you know that there are 2 sets of sides, a set that will be the size of the length and a set that will be the size of the width, so you multiply the width by 2 then multiply the length by 2 and add them
1*2 = 2
.5 * 2 =1
2+1 = 3
