How many revolutions will a circular disk with a diameter of 4 feet have to complete after it has rolled 20 feet?
Question:
How is this done without trigonometry? Every time I see the word REVOLUTIONS, I quickly think trigonometry.
The distance rolled in a single revolution is the circumference of the disk. This is pi(d), where d is the diameter. So, in this case that is 4•pi.
To get the number of revolutions can I divide 20 by 4pi?
Let R = number of revolutions
Let C = circumference
R = 20/C
R = 20/4•pi
R = 5/pi
Is this right?