How to find displacement of 400m track

[Rbraind]

Homework Statement

I know this is basic but I'm stumped

Homework Equations

a runner runs 6.5 laps around a 400m track, what's the displacement. I thought it would be 200m but the answer provided says 160m and I just can't work out how to get to this answer

The Attempt at a Solution

 

[gneill]

You might need some more details about the shape of the track and the runner's starting point.

 

[tedbradly]

Displacement will equal the length of the shortest line possible drawn from the starting point to the ending point. As you can see, if the track has any curvature at all during that half of a lap, the displacement will be less than 200 m.

 

[Rbraind]

Thanks people for your help. However I'm an idiot! Just realized there was a diagram with the question and the displacement marked in...