To calculate the area of the black material on the flag, we need the shape and the dimensions of the black material itself.
<em>Since the question is incomplete, as the dimension of the flag and the dimension of the black material are not given, I will provide a general explanation</em>
<em />
Assume the shape of the black material is a rectangle.
The area will be calculated as:

Take for instance;

The area is:


Assume the shape of the black material is a square.
The area will be calculated as:

Take for instance;

The area is:


Assume the shape of the black material is a triangle
The area will be calculated as:

Take for instance;

The area is:


So, in general.
You need to first get the shape of the black segment on the flag, then calculate the area using the appropriate formula.
Related link:
brainly.com/question/24251781