SOLUTION: You walk 45 degrees around the circumference of a circle that has a radius of 4 meters. To the nearest tenth, you have walked  A 1 m B 3.14 m C 6.28 m D 12.6 m

Algebra ->  Circles -> SOLUTION: You walk 45 degrees around the circumference of a circle that has a radius of 4 meters. To the nearest tenth, you have walked  A 1 m B 3.14 m C 6.28 m D 12.6 m      Log On


   

Question 598272: You walk 45 degrees around the circumference of a circle that has a radius of 4 meters. To the nearest tenth, you have walked 
A 1 m
B 3.14 m
C 6.28 m
D 12.6 m
Answer by math-vortex(648) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, there--
.
To find the distance around a circle you find the circumference.
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The circumference formula is
C=2%2Api%2Ar
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where C is the circumference and r is the radius of the circle.
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Substitute 45 for r in the equation. Do not round pi until the end of the problem.
C=2%2Api%2A%284%29
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Simplify.
C=8%2Api
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So, if you walked all the way around this circle you would walk 8*pi meters (a little more than 24 m). However you only walk 45 degrees around. We need to know what fraction of the circle that represents.
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There are 360 degrees in a full circle, so 45 degrees represents
45%2F360=1%2F8
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If you walk around 1/8 of the circle you walk 1/8 of the total circumference.
%281%2F8%29%288%2Api%29=pi
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You will walk pi meters. A good approximation for pi is 3.14. B is the correct answer. (one minor detail...3.14 is the best answer, but it is not rounded to the nearest tenth. That would be 3.1 meters.)
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Cheers!
Ms.Figgy
math.in.the.vortex@gmail.com