Answer:
30cm
Explanation:
Lets consider rectangle 1 and 2 as the top and bottom horizontal ones and rectangle 3 as the vertical one.
The rectangle 1 and 2 align to form a side with total length of 6cm and rectangle 2 and 3 align to form a side with length 9cm.
So perimeter of the bigger rectangle is Perimeter= 2(l+b) = 2(6+9) = 30cm