What do you need?
The perimeter is L + w + L + perimeter of a semicircle.
L = 22 cm
W = 18 cm
Perimeter can be one of two answers. You need to specify where the semicircle is. Formula for semicircle is
pi * r
r = 18/2 = 9 or
r = 22/2 = 11
So the perimeter of the semi circle is pi * 9 = 25.12 The total Perimeter = 22 + 22 + 18 + 25.12 = 87.12
It can also be 22 + 18 + 22 + 34.54 = 96.54 There are even more possiblities for perimeter. I would have the same problem if you asked about area.
Why not put more details in and I'l give you the correct answer. Here is what we need to know
1. Where is the circle on the 22 cm side or the 18 cm side?
2. What are you looking for: perimeter or area? As soon as you answer these I'll be back.