# Definition:Imperial/Area

## Definition

The imperial units of area are based on a system of units in which each unit is the square of a corresponding imperial length unit.

The imperial units of area are as follows:

### Square Inch

One square inch is equal to a square of side $1$ inch in length.

 $\ds$  $\ds 1$ square inch $\ds$ $=$ $\ds 6 \cdotp 4516 = 2 \cdotp 54^2$ square centimetres

The definition is exact.

### Square Foot

One square foot is equal to a square of side $1$ foot in length.

 $\ds$  $\ds 1$ square foot $\ds$ $=$ $\ds 144 = 12^2$ square inches

### Square Yard

One square yard is equal to a square of side $1$ yard in length.

 $\ds$  $\ds 1$ square yard $\ds$ $=$ $\ds 9 = 3^2$ square feet $\ds$ $=$ $\ds 1296 = 36^2$ square inches

### Square Rod, Pole or Perch

One square rod, pole or perch is equal to a square of side $1$ rod, pole or perch in length.

 $\ds$  $\ds 1$ square rod, pole or perch $\ds$ $=$ $\ds 30 \dfrac 1 4 = \paren {5 \dfrac 1 2}^2$ square yards $\ds$ $=$ $\ds 272 \dfrac 1 4 = \paren {16 \dfrac 1 2}^2$ square feet

### Square Chain

One square chain is equal to a square of side $1$ chain in length.

 $\ds$  $\ds 1$ square chain $\ds$ $=$ $\ds 16 = 4^2$ square rods, poles or perches $\ds$ $=$ $\ds 484 = 22^2$ square yards

### Rood

One rood is equal to an oblong measuring $1$ chain by $2 \frac 1 2$ chains.

 $\ds$  $\ds 1$ rood $\ds$ $=$ $\ds 2 \tfrac 1 2$ square chains $\ds$ $=$ $\ds 40$ square rods, poles or perches $\ds$ $=$ $\ds 1210$ square yards $\ds$ $=$ $\ds 10 \, 890$ square feet ### Acre

One acre is equal to an oblong measuring $1$ chain by $1$ furlong.

That is, measuring $4$ rods, poles or perches by $10$ chains.

 $\ds$  $\ds 1$ acre $\ds$ $=$ $\ds 4$ roods $\ds$ $=$ $\ds 10$ square chains $\ds$ $=$ $\ds 160 = 4 \times 40$ square rods, poles or perches $\ds$ $=$ $\ds 4840 = 22 \times 220$ square yards ### Square Mile

One square mile is equal to a square whose side measures $1$ mile.

 $\ds$  $\ds 1$ square mile $\ds$ $=$ $\ds 640$ acres