\begin{definition}[Definition:Imperial/Area/Square Rod, Pole or Perch]
The '''square rod, pole or perch''' is an imperial unit of area.
One '''square rod, pole or perch''' is equal to a square of side $1$ rod, pole or perch in length.
{{begin-eqn}}
{{eqn | o = 
      | r = 1
      | c = '''square rod, pole or perch'''
}}
{{eqn | r = 30 \dfrac 1 4 = \paren {5 \dfrac 1 2}^2
      | c = square yards
}}
{{eqn | r = 272 \dfrac 1 4 = \paren {16 \dfrac 1 2}^2
      | c = square feet
}}
{{end-eqn}}
\end{definition}