SOLUTION: A song on a 45 rpm record was 270 seconds long. How many degrees did the record rotate during the song?

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Question 576243: A song on a 45 rpm record was 270 seconds long. How many degrees did the record rotate during the song?
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
Each rotation is 360° so 45rpm = 45×360° rotations/minute

We convert 45 revolutions/minute to degrees/second

We begin with this fraction:

45rev%2F%28min%29

Each revolution is 360 degrees, so we multiply by this unit fraction 360deg%2F%281rev%29.  So we have:

45rev%2Fmin×360deg%2F%281rev%29  

Each minute is 60 seconds so we multiply by the unit fraction 1min%2F%2860sec%29

45rev%2Fmin×%28360deg%29%2F%281rev%29×%281min%29%2F%2860sec%29

We cancel the rev's and the min's

45cross%28rev%29%2Fcross%28min%29×360deg%2F%281cross%28rev%29%29×1cross%28min%29%2F%2860sec%29

expr%2845%2A360%2F60%29deg%2F%28sec%29

That comes out to 

270 degrees per second.

So 270 seconds at 270 degrees per second is a rotation through 270×270
or 72900 degrees.

Edwin