Question

the cross section of a Canal is in the shape of a Trapezium if the canal is 12 m wide at the top and 8 M wide at the bottom and the area of the cross section is 84 m square determine the depth

Answer 1

A=1/2(a+b)h [A=area,a=top wide,b=bottom wide,h=depth]
now,
h=2A/(a+b)
=2×84÷(12+8)
=8.4 m