Question

The cross-section of a canal is a trapezium in shape. If the canal is 10 m wide at the top 6 m wide at the bottom and the area of cross-section is 72 m² determine its depth.

Answer 1

$$\begin{gathered} \text{Let the depth of canal be}d\text{.} \\ \text{Given:} \\ \text{Lengths of the parallel sides of the trapezium shape canal are 10 m and 6 m.} \\ {\text{And, the area of the cross section of the canal is 72 m}}^2\text{.} \\ \text{Area of trapezium=}\frac{1}{2}\text{×(Sum of the parallel sides)×(Perpendicular distance between the parallel sides)} \\ 72=\frac{1}{2}\times \text{(10+6)×}\left(d\right) \\ 72=8\text{×}d \\ \text{d =}\frac{72}{8}\text{= 9 m} \end{gathered}$$