\begin{definition}[Definition:Imperial/Length/Rod, Pole or Perch]
The '''rod, pole or perch''' is an imperial unit of length.
{{begin-eqn}}
{{eqn | o = 
      | r = 1
      | c = '''rod, pole or perch'''
}}
{{eqn | r = 5 \tfrac 1 2
      | c = yards
}}
{{eqn | r = 16 \tfrac 1 2
      | c = feet
}}
{{eqn | r = 502 \cdot 92
      | c = centimetres
}}
{{eqn | r = 5 \cdotp 0292
      | c = metres
}}
{{end-eqn}}
\end{definition}