What are quadrilaterals?
Another type of polygon has four side and is called a quadrilateral. The sum of its four angles equals 360. The sum of the length of its sides is the perimeter. There are six kinds of quadrilaterals: A parallelogram has four sides. Each pair of opposite sides are parallel. A square has four equal sides, and each of its four angles is 90. A rectangle is a parallelogram with each of its four angles equal to 90. A rhombus has four equal sides. Two of its angles are obtuse, or greater than 90. A trapezium has only two sides that are parallel. A trapezoid has no sides which are parallel. Polygons can have more than three or four sides. For example, a pentagon has five sides; a hexagon, six; a heptagon, seven; an octagon, eight; and a dodecagon, twelve. What is a circle? As the number of sides increases and approaches infinity, the polygon takes on a new shape. It becomes a circle. A circle is a curved line, every point on which is the same distance from the centre. Every circle has 360. The
