Question

If the wheels of a rain make 16 revolutions when it rolls a distance of 60 feet, what is the radius of the wheel?
(a) 8/15pi
(b) 15pi/8
(c) 15/8pi
(d) 8pi/15
(e) 15/pi

Answer 1

when the wheel makes one revolution it should roll a distance equal to the circumference of the wheel. do you know the formula for the circumference of a circle with radius r?

Answer 2

yeah 2pir

Answer 3

good, so for 16 revolutions, the wheel will roll a distance equal to 16 times the circumference. so what you need to solve is:\[16\times2\pi r=60\]and solve for r.

Answer 4

i got r=1.875pi

Answer 5

leave it as a fraction please

Answer 6

(since your answer choices are in fractional form)

Answer 7

so is the answer (b)?

Answer 8

how did you get that answer? can you please show your steps?

Answer 9

so that I can help spot where you may have gone wrong.

Answer 10

well 1.875 is equal to 15/8 right?

Answer 11

how did you get to 1.875?

Answer 12

remember we started from:\[16\times2\pi r=60\]

Answer 13

please show each step that you took from here

Answer 14

oh i see what is did wrong. r is supposed to equal 1.875/pi right?

Answer 15

yes - but you need to leave it in fractional form

Answer 16

so it's (c) 15/8pi

Answer 17

perfect - well done! :)

Answer 18

thanks for the help

Answer 19

yw :)