which quadrilateral angles are congruent
Because the interior angles of a quadrilateral is 360Â° , we know that the remaining two angles must have a sum of 180Â° (because 360-180=180). Opposite angles of parallelograms are congruent, which means that each other the missing angles must have a measure of 90Â° (since 180Ã·2=90). This tells us that there are actually four right angles in Parallelogram C, so we know that it is a square (and a rhombus).