A quadrilateral is a four-sided shape that has four angles. The angles of a quadrilateral can be either right angles, acute angles, or obtuse angles. Identifying the type of quadrilateral can be a difficult task. To help you, here is an answer key to identify the type of each quadrilateral.

Parallelogram

A parallelogram has two sets of parallel sides and its opposite sides are equal in length. Its angles can be either right angle, acute angle, or obtuse angle. A parallelogram can also be identified by its diagonals, which bisect each other. Thus, if the diagonals of a quadrilateral bisect each other, then it is a parallelogram.

Rectangle

A rectangle is a special type of parallelogram where all its angles are right angles. It has two sets of parallel sides and its opposite sides are equal in length. A rectangle can also be identified by its diagonals, which bisect each other. Thus, if the diagonals of a quadrilateral bisect each other, and all its angles are right angles, then it is a rectangle.

Square

A square is a special type of rectangle where all its sides are equal in length. It has four right angles. A square can also be identified by its diagonals, which bisect each other. Thus, if the diagonals of a quadrilateral bisect each other, and all its sides are equal in length, then it is a square.

Trapezoid

A trapezoid has two sets of parallel sides and one set of non-parallel sides. Its angles can be either right angle, acute angle, or obtuse angle. A trapezoid can also be identified by its diagonals, which do not bisect each other. Thus, if the diagonals of a quadrilateral do not bisect each other, then it is a trapezoid.

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Identifying the type of a quadrilateral can be difficult. However, with this answer key, you can easily identify the type of each quadrilateral. The key is to look at the diagonals of the quadrilateral and the angles of the quadrilateral. If the diagonals bisect each other, then it is a parallelogram, rectangle, or square. If the diagonals do not bisect each other, then it is a trapezoid.