ANSWER
A = 1.571 square units
Step-by-step explanation
The diameter of the semi-circle is 2 units.
To find the area, first we need the radius.
Radius is half the diameter, so:
Radius, r = D / 2
Radius, r = 2 / 2
r = 1 unit
The area of a semi-circle half that of a circle.
A circle's area is:

So, a semi-circle's area is:

That is the area.