Answer
$A= \pi \approx3.14 \text{ square units}$
Work Step by Step
The area of the shaded region is equal to the area of the circle.
The circle has a diameter of 2 units.
The radius is one-half of the diameter.
Thus,
radius $=0.5(2) = 1$ unit.
The area of a circle whose radius is $r$ units is given by the formula:
$A = \pi{r^2}$
Solve for the area of the shaded region by using the formula above and that radius of $1$ unit to obtain:
$\text{area of shaded region}
\\= \text{area of circle}
\\= \pi(1^2)
\\= \pi(1)
\\= \pi \approx3.14 \text{ square units}$