# Arc length trig vector problem

1. Jan 26, 2008

### torresmido

I need help with this homework problem:

Making a turn, a jetliner flies 2.1km on a circular path of radius 3.4km. Through what angle does it turn?

Any ideas that would help me in doing it??

thanks

2. Jan 26, 2008

### BryanP

*hint* arc length in trig.

3. Jan 26, 2008

### _Mayday_

Why don't you try the forum specifically for homework, you will probably get more help there.

4. Jan 26, 2008

### billiards

Draw a diagram.

5. Jan 26, 2008

### _Mayday_

The formula for calculating the circumference $$\pi d$$. You have the radius which is half the diametre, so in this case the diametre is 6.8. Now plug those figures into the formula. It should look like this...

$$\pi 6.8 = 21.35$$

Now that you have the total circumference, you want to find out what fraction of the circumference the plane travels. I would do this by trying to find what 1 degree is, so I would go

$$\frac{360}{21.35}$$

Now that you have what 1 degree is in relation to a length, you simply multiply

$$\frac{360}{21.35}2.1$$

This will give you the angle in which the plane has travelled. It should be around 36 degrees but I will let you finish it off.

If you are having any trouble just say