The are of the trapezoid can be calculated by parts:
First part: rectangle of 12 by 18 ==> area = 12 * 18 = 216
Second part: triangle on the right with height 12 and we don't know the base but we can calculate it by pythagoras:
12² + base² = 15² ==> base² = 15² - 12² = 225 - 144 = 81 ==> base = 9
Then the area of the triangle on the right is (b * h)/2 = (9 * 12)/2 = 54
Third part:
triangle on the top of the figure, it has a heihgt of 1 and a base of 18, so its area is (b * h)/2 = (18 * 1)/2 = 9
Adding all the parts: 216 + 54 + 9 = 279
Answer:
Area = 279