Question 692963: find the circumference of a circle wth radius 7 in
Found 3 solutions by jim_thompson5910, fcabanski, RedemptiveMath:
Answer by jim_thompson5910(35256)   (Show Source):
Answer by fcabanski(1391) (Show Source):
You can put this solution on YOUR website! Circumference is 2*pi*r. In this case it's 2*pi*7 = 14pi = approximately 44 inches.
Hope the solution helped. Sometimes you need more than a solution. Contact fcabanski@hotmail.com for online, private tutoring, or personalized problem solving (quick for groups of problems.)
Answer by RedemptiveMath(80) (Show Source):
You can put this solution on YOUR website! The standard formula for finding the circumference of a circle is C = d * π or C = 2r * π, where d = the diameter, r = radius, and π = a value of approx. 3.14159 or 22/7 (depending on the context of the problem). The reason we could use either formula is because twice the radius of a circle equals its diameter, or 2r = d. So, we could use either or to solve for the circumference. Using our values, we have:
C = 2rπ
C = 2(7)(22/7)
C = 14(22/7) = approx. 44 in. (43.982 in).
C = dπ = 14(22/7) = approx. 44 in. (43.982 in).
OR
C = 14(3.14159) = approx. 44 in. (43.982 in).
NOTE: Depending on your course, it is extremely important to note the usage of pi in these answers. I have calculated the approximate value of pi and use that in my operations. Pi is not a constant number; it is irrational (never-ending decimal). If the problem wants the EXACT answer for this, then we need to simply leave the symbol for pi in our answer:
C = 14π in.
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