Question

The cross-section of a canal is in the form of a trapezium. If the canal top is $10m$ wide and the bottom is $6m$ wide, and the area of cross-section is $72m^2$, then the depth of the canal is

• A. $10m$
• B. $7m$
• C. $6m$
• D. $9m$

Answer 1

The correct option is D $9m$

As we know the area of trapezium $=\frac{1}{2}\times \left(sumofparallelside\right)\times height$

$72m^2=\frac{1}{2}\times (10+6)\times depth$

$72m^2=\frac{1}{2}\times 16\times depth$

$72m^2=8\times depth$

Depth $=\frac{72}{8}$

Depth $=9m$