9. Evaluate the length of table

The shape of the top surface of a table is a trapezium and its area is 416 \(m²\). One of the parallel sides measures 7 \(m\) and the perpendicular distance between them is 4 \(m\). Find the length of other parallel side.

 

  

Answer: The length of other parallel side \(b\) of a table is  \(m\).