I am doing an MTO for work and need to calculate a swale concrete lining. On
paper, easy. But I cannot get the formula to work on excel.

Obviously you have SQRT(number) and a couple of POWER(number) x thickness x
length but I cannot get it to work.

The slope of the swale is 1.5 times the base, therefore you have 1.5 x b
squared + d squared and then this answer is sqrt x 2 for both sides + b for
total length x thickness x length.

to get this all in one formula is mind boggling to me, or maybe I need a
break, short fuse and all that.