The cross-section of a cannel is a trapezium in shape. If the cannel is 10 m wide at the top and 6 m wide at the bottom and the area of cross-section is 640 sq m, the depth of cannel is?
Pick one
A) 20 m B) 60 m C) 40 m D) 80 m E) 90 m
1/2 * d (10 + 6) = 640   d = 80   ANSWER:80 m
<result>D</result>
The cross-section of a cannel is a trapezium in shape. If the cannel is 10 m wide at the top and 6 m wide at the bottom and the area of cross-section is 640 sq m, the depth of cannel is?