Classifying Quadrilaterals and Triangles

A quadrilateral is a polygon with four sides, four vertices, and four angles.

The different types of quadrilaterals include squares, rectangles, rhombuses, parallelograms, trapezoids, and kites.

A triangle is a polygon with three sides, three vertices, and three angles.

The types of triangles based on sides are equilateral (all sides equal), isosceles (two sides equal), and scalene (no sides equal).

The types of triangles based on angles are acute (all angles less than 90°), right (one angle is 90°), and obtuse (one angle is greater than 90°).

A right angle is an angle that measures exactly 90 degrees.

A parallelogram is a quadrilateral with two pairs of parallel sides.

A rectangle is a quadrilateral with four right angles and opposite sides that are equal in length.

A square is a quadrilateral with four equal sides and four right angles.

A trapezoid is a quadrilateral with at least one pair of parallel sides.