The 8 is the side of the rectangle and so is the 16. 8x16=128. 128 is the area for the rectangle. The 12 is the side of the rectangle (8) and side of the triangle (4). The 10 comes from the side of the rectangle (16) minus the base of Triangle (6).
Now 8x16=128
area for a triangle is A= a basexheightxhalf
6*4*.5=12
12 plus 128 equals 140
