Answer:
You cant convert a linear measurement into an area measurement. However, if you have an area that you want to measure in sq. centimeters and you know the perimeter this is how you would do it:
5 cm
____________
l___________ l
l___________ l
l___________ l
l___________ l 6 cm
l___________ l
l___________ l
6 X 5 = 30
The above figure is 30 sq cm.