#### Answer

(a) rhombus
(b) rectangle

#### Work Step by Step

(a) A quadrilateral with four congruent sides is a rhombus.
(b) A quadrilateral that is a parallelogram with a right angle is a rectangle. Note that if one angle of a parallelogram is a right angle, then the opposite angle is a right angle. Then all four angles must be right angles since the sum of the angles is $360^{\circ}$