To find circumference and area knowing that the radius is 5.2, you have to use the formula of circumference and area of a circle. For circumference, you plug 5.2 as r in C=2(pi)(r), which would be C=2(pi)(5.2). In terms of pi, it would be 10.4 pi cm because 2 and 5.2 are multiplied together and the pi stays isolated. For area however, you use A= pi (r squared), and plug 5.2 for r, just like circumference. The resulting equation is A=pi(5.2 squared), which would be A=27.04pi cm squared.
Here is some work:
C=2(pi)(r)
C=2(pi)(5.2)
C=10.4pi cm
A=pi (r squared)
A=pi ( 5.2 squared)
A= 27.04pi cm squared
Here is some work:
C=2(pi)(r)
C=2(pi)(5.2)
C=10.4pi cm
A=pi (r squared)
A=pi ( 5.2 squared)
A= 27.04pi cm squared
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Circle...right ?
Circumference = 2π r
Area = π r^2 [area is measured in square units]
qed
Circumference = 2π r
Area = π r^2 [area is measured in square units]
qed