Question

A wheel has a diameter of 21 inches.

Approximately how far does it travel in 3 revolutions?



A.
63 in.


B.
65.94 in.


C.
98.91 in.


D.
197.82 in.

Answer 1

@MonKiwi

Answer 2

I think A

Answer 3

because 21 x 3 = g3

Answer 4

63* i meant

Answer 5

i would think its A as well, but i would like to have it confirmed just to be sure.

Answer 6

yeah, okay.

Answer 7

@johnweldon1993

Answer 8

A is not the answer

Answer 9

Why?

Answer 10

@UsukiDoll

Answer 11

@unknownunknown

Answer 12

Keys:
C=Circumference
D=Diameter
R=Radius
3.14=pi
How to find the circumference:
D=21
Divide that by 2
= 10.5
The formula for the circumference of a circle is
2×3.14×r
Plug in the numbers:
2×3.14×10.5
Which equals 65.94
Then, we have to multiply that by 3. So,
65.94 x 3 = 197.82
Which is our answer.

Answer 13

@geerky42

Answer 14

So, remember c/d = pi.

Re-arrange to get c = pi * d

One circumference of a circle is equivalent to a full revolution. So we multiply by 3 for 3 revolutions.

pi * d * 3 = 197.82, as YoungTrilogy stated.

Answer 15

okay, thank you :) √