What do all of these polygons have in common?

a. each appears to have exactly two pairs of parallel sides.
b. each appears to have exactly one pair of parallel sides.
c. each appears to be a quadrilateral.
d. each appears to be a trapezoid.

The bottom of ignacio's desktop is 74.5cm from the floor. ignacios sits in his adjustable chair, and the tops of his legs are 49.3cm from the floor. each clockwise rotation of the knob on the chair raises ignacio's legs by 4.8cm. write an inequality to determine the number of clockwise rotations, r, ignacio could make with the knob without his legs touching the desk.