The

most

common

unit

was

the

foot.

To

measure

the

distance

of

a

path,

someone

walked

heel-

to-

toe

along

it

and

counted

each

time

they

set

down

a

foot.

If

they

set

down

their

feet

20

times,

the

path

was

20

feet

long.

However,

there

was

a

problem

with

using

bodies

as

units

of

measure.

People

are

not

all

the

same

size,

so

the

units

were

not

always

the

same.

People

with

smaller

feet

would

measure

distances

differently

than

people

with

larger

feet.