Remark
You don't have to decompose the second one, and it is better if you don't. Just find the area as you probably did: use the formula for a trapezoid. You have to assume that the 6cm line hits the 2 bases at right angles for each of them, otherwise, you don't know the height. So I'm going to assume that we are in agreement about the second one.
Problem One
The answer for this one has to be broken down and unfortunately, you answer is not right for the total area, although you might get 52 for the triangle. Let's check that out.
Triangle
Area = 1/2 * b * h
base = 16 cm
h = 10 - 4 = 6
Area = 1/2 * 16 * 6
Area = 48
Area of the Rectangle
Area = L * W
L = 16
W = 4
Area = L * W
Area = 16 * 4
Area = 64
Total Area
Area = 64 + 48
Area = 112 of both figures <<<< Answer