What is the standard geometric name for a regular quadrilateral?
Tangential quadrilateral "inscriptible quadrilateral", "inscribable quadrilateral", "circumcyclic quadrilateral", and "co-cyclic quadrilateral". Due to the risk of confusion with a quadrilateral that has a circumcircle, which is called a cyclic quadrilateral or inscribed quadrilateral, it is preferable not to use any of the last five names. All triangles have an incircle, but not all quadrilaterals do. An example of a quadrilateral that cannot be tangential is a non-square rectangle. The section characterizations below states what necessary and sufficient conditions a quadrilateral must satisfy to have an incircle. Examples of tangential quadrilaterals are the kites, which include the rhombi, which in turn include the
Geometric standard deviation Geometric standard deviation In probability theory and statistics, the geometric standard deviation describes how spread out are a set of numbers whose preferred average is the geometric mean. For such data, it may be preferred to the more usual standard deviation. Note that unlike the usual "arithmetic" standard deviation, the "geometric" standard deviation is a multiplicative factor, and thus is dimensionless, rather than having the same dimension as the input values. Thus, the geometric standard deviation may be more appropriately called geometric SD factor . When using geometric SD factor in conjunction with geometric mean, it should be described as