question_answer

The cross-section of a canal is a trapezium in shape. If the can I is 8m wide at the top and 6 m wide at the bottom and the area of cross-section is 644 sq m, then the length of the canal is

A)  90 m                

B)         92 m  

C)  94 m                    

D)  96 m

Correct Answer: B

Solution :

 If h is the length, then by hypothesis \[\frac{1}{2}\,(8+6)\times h=644\]                 or            \[7h=644\]                 \[\therefore \]  \[h=92m\]