The cross section of a canal is a trapezoid in shape. If its width is 10 m wide at the top and 6 m wide at the bottom and the area of cross-section is $675\;m^2$, what can be the length of the canal ?

Question

$\begin{array}{1 1} (a)\; 80\; m \\(b)\; 82\;m\\(c)\;84\;m\\(d)\;85\;m\end{array}$