00:01
All right, i think this is an arc length problem just designed with a ferris wheel.
00:05
So if you can imagine what's going on here, you have your circle.
00:10
They tell you that the radius is 11.
00:15
And they said that the ferris wheel has to start at three o 'clock.
00:18
Well, three o 'clock's right here, right? three o 'clock right here.
00:22
So that is zero degrees or zero radians, right? all right, then it tells you, imagine an angle with the vertex at the center of the ferris wheel.
00:32
So there's your angle, center of the ferris wheel, that subtends the arc along which kristen travels.
00:39
So you can imagine that this is coming up here.
00:42
So what we got going on there then is theta is this little angle down here.
00:47
And this is your arc length right here.
00:50
This is your s.
00:53
And the formula that relates all this is s equals r theta.
00:57
The trick to this is making sure that theta is in radians and making sure your calculator is in radians.
01:04
So if your calculator is not in radians, you wanna select the mode button and make sure that it says radians.
01:10
Scroll down till it's in there and press enter to make sure it's highlighted, all right? then the first question reads, if kristen travels 13 .2 meters, what is the angle's measure in radians? so i just need this formula, s equals r theta.
01:27
I don't know why that didn't print, s equals r theta.
01:30
So that first one said she traveled 13 .2 meters.
01:35
We know the radius is 11 and they want us to find a theta.
01:41
So you're literally dividing by 11.
01:44
So calculator work, 13 .2 divided by 11 gives you 1 .2 radians...