ANSWER
A = 1.571 square units
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:
[tex]A=\pi\cdot r^2^{}[/tex]So, a semi-circle's area is:
[tex]\begin{gathered} A\text{ = }\frac{1}{2}\pi\cdot r^2 \\ \Rightarrow\text{ A = }\frac{1}{2}\cdot\text{ }\pi\cdot1^2 \\ (\pi\text{ = 3.142}\ldots) \\ \Rightarrow\text{ A = 1.571 square units} \end{gathered}[/tex]That is the area.
