Answer:
17
Explanation
Using the formula: A= base1 + base 2/ 2 *h
The base you are looking for will be named a;
a = 2 a/h - b 2*112/8 - 11 =17
first a is base a. = 2 times area divided by height minus base b which is 2 times 112 over 8 minus 11 which gives you the answer of 17