it looks like you're finding the circumference. for future reference, remember this:
"twinkle twinkle Little Star, circumference equals 2 pi R!"
2piR is the formula for this. R = Radius
To get the radius, you must divide the diameter by 2. 8/2 = 4
Next, multiply 2 by 3.14 (pi) and 4.
2x3.14x4 = 25.12
So, In this case, the answer is 24
Obviously, people use different versions for pi so answers vary.
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Answered by indeedlindsey, pre algebra honors