18. Which classification of quadrilateral has only one pair of opposite sides that are parallel?
C. rhombus
D. trapezoid
A. square
B. rectangle
19. What do you call a quadrilateral whose opposite sides are equal and has 4 right angles?
A. triangle
B. rectangle
C. trapezoid
D. rhombus
20. Is a parallelogram a rectangle?
A. Yes
B. No
C. A and B
D. All of the above​