Answer: 
Step-by-step explanation:
To solve this problem you must apply the proccedure shown below:
- By definition, the perimeter of the figure is the sum of the lenght of each side. Then, you must make the addition as following:

Where
is the perimeter of the figure.
- Add the like terms, then, you obtain the following expression in simplest form:

This is a 52% increase.
The answer and the work is attached in the image provided.
Circumference=diamter times pi
diamter=2 times radius
circumference=radius times 2 times pi
circunference=135.648
aprox pi to 3.14
subsitute
135.648=radius times 2 times 3.14
135.648=radius times 6.28
divide both sides by 6.28
21.6=radius
aswe ris radous=21.6 units
Answer:
I believe the answer is multiplication property of equality.
I hope I helped, please correct me if I'm wrong!