Explanation:
the first : e.g. a trapezoid
only 2 lines are parallel, but still it is a closed object with 4 vertexes and therefore 360° sum of internal angles. and 2 of the angles are smaller than 90°, and 2 are larger than 90°.
the second : a parallelogram, with all 4 sides having the same length. a square that is pushed e.g. on the top while the bottom stays.
the third : a rectangle. perpendicular means intersecting at 90°. but not a square. length and width must be different.
that's it, really. what was so confusing for you ?