Question

8. Mark is sitting in a chair, legs out in front of him resting on an ottoman. His knees are.....

Answer 1

His knees are flat in front of him or 180 degrees, i hope that answered your question   

Answer 2

Yep! If legs are in front of him, then his legs are straight in perpendicular direction, so his knees are making 180 degree of angle..

Hope it helped.