Shaded triangle area (triangle base is 4 and height is 4)

4*4/2=8 square meters

Right:

Algorithm 1:

Another penumbral triangle with different shadow areas has a base of (6-4)=2 from the left, a height of 6 and an area of 2*6/2=6.

Sum of triangle areas of two parts: 6+8= 14 square meter.

Algorithm 2:

The sum of the areas of two squares minus the triangular area of two white parts.

6 * 6+4 * 4-6 * 6/2-(6+4) * 4/2 =14 square meter