Quadrilateral

1. a quadrilateral which has all its four vertices lying on a circle.
5. a trapezoid is a four-sided shape with one pair of parallel sides, like a stretched-out rectangle.
9. a convex quadrilateral that has both an incircle and a circumcircle.
10. a special case of a trapezoid. Alternatively, it can be defined as a in which both legs and both base angles are of the same measure.
12. a quadrilateral with all four sides having equal lengths. The Opposite sides of a rhombus are parallel and opposite angles are equal.
13. is a closed shape that is formed by joining four points among which any three points are non-collinear.
14. is a quadrilateral with two pairs of parallel sides.

2. a quadrilateral which has one of its interior angles greater than 180°.
3. a quadrilateral that has 2 pairs of equal-length sides and these sides are adjacent to each other.
4. is a quadrilateral that can be inscribed in a circle (cyclic quadrangle) in which the products of the lengths of opposite sides are equal.
6. having all the internal angles equal to 90 degrees.
7. a four-sided polygon that has interior angles that measure less than 180 degrees each.
8. a Euclidean quadrilateral with one concave angle that is formed by joining two triangles with.
10. a quadrilateral with four sides that are not regular or the same.
11. a regular quadrilateral, which has all the four sides of equal length and all four angles are also equal.