How Far Does an Object Travel on a 4m Diameter Circle with a 45 Degree Shift?

[Emethyst]

Homework Statement

An object travels in a circular trajectory that has a diameter of 4m. From start to finish the change in the angle of movement is 45 degrees. How far has the object travelled?

Homework Equations

Circumference formula

The Attempt at a Solution

I started by drawing out a circle and filling in the info given. From what was supplied in the question, I decided to use the circumference formula and then divide the answer obtained by 8 to take into account the change of angle. The answer I came up with was 1.6m. I'm not sure if this is correct because I'm not supposed to have to use a calculator to come up with the answer, so I'm not sure if I'm doing something wrong. If anyone can point out any mistakes I could've made it would be greatly appreciated, thanks in advance.

 

[rock.freak667]

In 360 degrees it travels πd meters
in 45 degrees how far does it go??