Answer:
The perimeter is 55.68 cm.
Explanation:
We have 2 sides as 9 cm. 
We have the diameter as 12 cm. So, radius = 6 cm
Circumference of complete circle is = 
 So, circumference of half circle will be
 So, circumference of half circle will be 

Now the perimeter of the whole figure will be given as:

= 

= 

= 55.68 cm
Therefore, the perimeter is 55.68 cm.