a quadrilateral is a polygon with 4 sides
yes, when opposite angles and sides are congruent
Quadrilaeral has 4 sides and the sum of angles of 180*2=360 The above awnser is right, but heres a simpler awnser: A quadrilateral is a closed foursided shape. (closed means all the sides are connected togethere with both sides next to them). A square is a quadrilateral For most quadrilaterals it is 'length times perpendicular height' and measured in square units. * * * * * The answer given for the area is true only for a small number of quadrilaterals which contain two pairs of parallel lines. The answer for most quadrilaterals is that they need to be divided into two triangles , the area of each calculated and the results added together.