You have to use composites here since this is not a regular polygon. It looks like you could split it up into a triangle and a parallelogram. The area of a triangle is [tex]A= \frac{1}{2} bh[/tex] while the area of a parallelogram is A=bh. Find the areas of both those shapes and then add them together. The triangle has a height of 3 units and a base of 5 units. Therefore, its area is 15/2. Now for the parallelogram. It has a height of 3 units and a base of 5 which is 15. So we will add those together: [tex]A= \frac{15}{2} +15[/tex], which, with a commond denominator is 45/2 or 22.5 units squared.
