Hello,

OK, so I understand the basic formula to work out area of aTrapezoid

A=(b+B)/2 *H

I understand thatbis the base width andBis the top width andHbeing height.

I need to work out the area for a Trapezoid that has been rotated 90 degrees, with in a river cross section.

So can I apply this formula to the height of either side of the section of river which would bebandBin the formula andHwhich now would be the width ?

Thanks for any help in advance