A rectangle is a plane figure with four straight sides and four right angles, esp. one with unequal adjacent sides. A square is a plane figure with four equal straight sides and four right angles. A rhombus is a parallelogram with opposite equal acute angles, opposite equal obtuse angles, and four equal sides.
A parallelogram does not equal 180. A parallelogram is a plane figure bounded by two pairs of parallel lines. What does equal 180 is the sum of the measures of any pair of adjacent angles. The two adjacent angles have a side in common. If that line is considered as the intercept of the pair of parallel lines, it is easy to show that the angles should add to 180 degrees.
Triangle is plane with three sides and three angles. The sum of its inside angles is equal to 180 degrees.
square or rhombus
a plane figure having six sides is a hexagon
A square is a plane geometric figure having 4 equal sides and 4 right angles.
A perfect square Four 90 degree angles and four equal sides
A regular polygon is a plane figure with equal sides and equal angles.