To determine the circumference and area of these circles, we must use the proper formulas.
For circumference : 2PiR (or PiD, which Pi = 3.14).
For area: PiR^2
Since we have the radius, let's get to solving!
The first circle (Circle1):
Our radius is 8cm, so let's work for it's circumference. Using our formula, we will multiply 8 by 2 by 3.14.
16 x 3.14 = 50.24.
Circle1's circumference is 50.24cm^2.
Now let's do the area for Circle1.
The radius, 8, squared is (8x8) 64.
64 x 3.14 = 200.96 cm^2.
The area for Circle1 is 200.96cm^2.
Now let's work with Circle2 (second circle).
The radius for that circle is 5cm.
Let's use our circumference formula.
5 x 2 x 3.14 = 10 x 3.14 = 31.4cm^2,
Our circumference for Circle2 is 31.4cm^2.
Now let's do the area for Circle2.
3.14 x 5^2.
25 x 3.14 = 78.5cm^2.
Our area for Circle2 is 78.5.
Let's compare our circumferences and our areas.
Circle1 to Circle 2's Circumference:
50.24:31.4
If we were to divide 50.24 by 31.4 we'd get 1.6.
Circle1 to Circle2's Area: 200.96:78.5.
If we were to divide 200.95 by 78.5 we'd get 2.56.
The circles are NOT similar.