Find the perimeter of the shaded region.

Answer:
The perimeter of the shaded region is [tex](3\pi+12)\ units[/tex]
Step-by-step explanation:
we know that
The perimeter of the shaded region is equal to the circumference of a semicircle (two quarter of circle) plus 12 units
The circumference of a semicircle is
[tex]C=\pi r[/tex]
we have
[tex]r=3\ units[/tex]
so
[tex]P=\pi (3)+12\\P=(3\pi+12)\ units[/tex]