the area has to be found step by step for this one since it doesn't really have a top part. so you say 6.5*28= 182 ft squared
then 6.5 * 13 * 2= 169 ft squared
and then find the last two sides which are
28 * 13= 364 ft squared
Finally you have to add all the above areas so, 182+169+364= 717 ft squared