how many times does a bicycle tire tat has a radius of 21 in rotate when it travels 420 in?
2006-09-24 06:37:52 · 5 answers · asked by juice. 3 in Education & Reference ➔ Homework Help
3
3.1831....to be exact
2πr
2π(21)
π42
420 / (π42) ≈ 3.1831, or 3
2006-09-24 06:39:28 · answer #1 · answered by nadrik 2 · 1⤊ 0⤋
Let x be the number of rotation that needs to travel at least 420 in.
Circum of circle = 2*pi*r
2*pi*r*x = 420, where x = 21
42*pi*x = 420
pi*x = 10
x = 10 / pi
therefore x = 4 to travel 420 in
2006-09-24 13:48:10 · answer #2 · answered by davidkwankwokfai 3 · 0⤊ 0⤋
The circumference of the tire will be 2 X 3.14 (Pi) X 21 (radius) = 131.9 in.
In other words, there will be one rotation whenever it travels a distance of 131.9 in.
Therefore when it travels a distance of 420 in, it would have had 420/131.9 = 3.18 rotations.
2006-09-24 13:48:15 · answer #3 · answered by Hobby 5 · 0⤊ 0⤋
You are to find the circumfrence of the tyre, and then find how many of the circumfrence that can be found in 420 ins.
Circumfrence=diametre*pie
=2*21*(22/7)=132
No. of times in 420ins=420/132=3.1818182 times.
2006-09-25 11:41:31 · answer #4 · answered by peaceman 4 · 0⤊ 0⤋
3.18
2006-09-24 16:08:36 · answer #5 · answered by sangreal 4 · 0⤊ 0⤋