To make sure that a given parallelogram is a rectangle, at least how many of its an...
Check the final answer first, then review the worked steps.
Problem
To make sure that a given parallelogram is a rectangle, at least how many of its angles must measure 90 degrees?
Step-by-step solution
A parallelogram is a rectangle if at least one of its angles is 90 degrees. In a parallelogram, consecutive angles are supplementary, and opposite angles are equal. If one angle is 90 degrees, its consecutive angles must also be 90 degrees (180 - 90 = 90). The opposite angle will also be 90 degrees.
Answer
Two