The circumference of a circle is 60π cm. What is the length of an arc of 140°?

Question

anonymous · Answer

what portion of the circle is 140 degrees, given that the whole circle is 360 degrees?

agent47 · Answer

hint: 360/140

anonymous · Answer

Hint: circumference of a circle = 2 pi r

agent47 · Answer

$$60\pi:360 = x:140$$

anonymous · Answer

Or u can find r

anonymous · Answer

there's not much point in finding r here

anonymous · Answer

it doesn't really get you any closer to the answer

anonymous · Answer

And use |dw:1347153816503:dw|

anonymous · Answer

Where theta is in radian

anonymous · Answer

what's the other symbol?

anonymous · Answer

S is the length of the arc

anonymous · Answer

what's the denominator?

anonymous · Answer

Its r----> radius of the circle

anonymous · Answer

that doesn't make sense, it would imply that larger circles have smaller arc lengths

anonymous · Answer

The best way to solve it is to solve the ratio 60π:360=x:140

anonymous · Answer

Ya..... its true... larger the circle larger the arc length

anonymous · Answer

Welp thats what it says on this work thing. Thank you for the help though! :) I'm not really sure what to do with the ratios at all. lol

anonymous · Answer

ok look at it this way, if 360 degrees is a complete circle, then 180 degrees is half the circle.  so what's 140 degrees?

anonymous · Answer

oh well it's not asking for percents thats the problem lol