The length of the arc is about 7pi/2 units, which is about 11 units.

If your answer **does not** match our answer,

- did you try using an actual triangle and square to model what happens?

- did you find that A doesn't move every time the triangle is rotated?

- and your answer is close, did you use a calculator early on and maybe round too much?

If your answer **does** match ours,

- have you carefully explained each step that you took?
- did you make any mistakes along the way? If so, how did you find them?
- did you try the extra?