These shapes are Rhomboids

In geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are oblique. Image File history File links Rhomboid. ... Image File history File links Rhomboid. ... Geometry (Greek γεωμετρία; geo = earth, metria = measure) arose as the field of knowledge dealing with spatial relationships. ... A parallelogram. ... Oblique can mean one of several things: In linguistics, oblique case. ...

A shape like a rhomboid with sides of equal length (equilateral) is a rhombus. In geometry, an equilateral polygon has all sides of the same length. ... This shape is a rhombus In geometry, a rhombus (also known as a rhomb) is a quadrilateral in which all of the sides are of equal length. ...

A shape like a rhomboid with right angled corners is a rectangle. This article is about angles in geometry. ... In geometry, a rectangle is defined as a quadrilateral polygon in which all four angles are right angles. ...

The word Rhomboid which means rhom-like was commonly used in the 19th century for a parallelogram which was neither a rectangle nor a rhombus. Today it is more often used for a solid figure with six faces in which each face is a parallelogram and opposite faces in pairs lie in parallel planes. Some crystals are formed in 3D rhomboids. It is also sometimes called a rhombic prism. The term shows up frequently in science terminology referring to both its two and three dimensional meaning. A parallelogram. ... In geometry, a rectangle is defined as a quadrilateral polygon in which all four angles are right angles. ... This shape is a rhombus In geometry, a rhombus (also known as a rhomb) is a quadrilateral in which all of the sides are of equal length. ...

Euclid introduces the term in his Elements in Book I, Definition 22, Of quadrilateral figures, a square is that which is both equilateral and right-angled; an oblong that which is right-angled but not equilateral; a rhombus that which is equilateral but not right-angled; and a rhomboid that which has its opposite sides and angles equal to one another but is neither equilateral nor right-angled. And let quadrilaterals other than these be called trapezia. [ Translation from the page of D.E.Joyce, Dept. Math. & Comp. Sci., Clark University [1] ]

Euclid never uses the definition of rhomboid again and introduces the word parallelogram in Proposition 31 of Book I; "In parallelogrammic areas the opposite sides and angles are equal to one another, and the diameter bisects the areas." Heath suggests that rhomboid was an older term already in use . A parallelogram. ...

References

• Heath, Sir Thomas L.
• The Thirteen Books of Euclid's Elements. 2nd ed. 3 vols. 1926; rpt. New York: Dover Publications, Inc., 1956.