Since 38-18=20, you divide by 10 to find the base of the two triangles on the side. The height of the triangle is 16 and the formula is basexheightx1/2.
10x16x0.5=80
You then multiply that by two because there are two triangles
80x2=160
You then have to find the rectangle in the center, which is 16x18=288 cm
