The formula for a trapezoid is a= 1/2*(b1+b2)*h. B1 and b2 would represent the two bases given and therefore doesn't matter what order you put them in. Plug in all values into the equation and you'll get 1/2*(5+8)*5 then 1/2*(13)*5. Next simplify to get 6.5*5 which then equates to 32.5.
