If the area of a trapezoid is a=1/2h(a +b) solve for h

The dolphins at the webster are fed 1/2 of a bucket of fish each day the sea otters are fed 1/2 as much fish as the dolphins how many buckets of fish are the sea fed each day? simplify you answer and write it as a proper fraction or as a whole or mixed number

Can someone me do math because i am having a breakdown rn because i don’t get it

How is working backward similar to solving an equation?