How many laps around 4 acres to equal a mile?

3.16

4 acres = 19360 square yards

IF the land is a square, one side = √19360 = 139 yards, and perimeter = 557 yards

1 mile = 1750 yards, so 1750 / 557 = 3.1 laps

IF the land is a circle, radius r = √(A/π) and circumference = 2πr = 2π √(A/π) = 493 yards

so 1750 / 493 = 3.5 laps

IF the land is a rectangle, 100 yards by 193.6 yards, perimeter = 2•293.6 = 587 yards

so 1750 / 587 = 3.0 laps

IF the land is a rectangle, 300 yards by 64.5 yards, perimeter = 2•364.5 = 729 yards

so 1750 / 729 = 2.4 laps

etc

etc

1 mile = 5280 feet

Perimeter of 4 acres:

4 (417.4) feet

Number of laps around 4 acres = 3.1624341159559175

define the shape of the area first, or you cannot know the length of the perimeter. An acre has no defined shape in modern usage. Historically, the idea would refer to a rectangle having a 10 to 1 side length (660ft by 66 ft), which would mean a perimeter of 2*(660+66)=1452 feet. 1452/5280 = 0.275, or you would run 0.275 miles each time you ran around that field. 1/0.275=3.64 laps per mile.

That would depend on its side lengths but there are 1760 yards in a mile.

Four acres could be a rectangle 417 x 418 feet. In that case, 3.16 laps is one mile.

Four acres could be 792 x 220 feet. In that case, 2.61 laps is one mile.

So it depends on the shape.

You can't calculate the permiter distance based solely on area.

What shape is it?