Rectangle
Rectangle
In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°). It can also be defined as a parallelogram containing a right angle. A rectangle with four sides of equal length is a square.
The term oblong is occasionally used to refer to a non-square rectangle. A rectangle with vertices ABCD would be denoted as 
ABCD.
The word rectangle comes from the Latin rectangulus, which is a combination of rectus (as an adjective, right, proper) and angulus (angle).
| Rectangle | |
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Rectangle
Video: Area of a Rectangle |
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Type
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quadrilateral, parallelogram, orthotope
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Edges
and
vertices
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4
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Schläfli symbol
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{ } × { }
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Coxeter diagram
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Symmetry group
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Dihedral (D2), [2], (*22), order 4
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Dual polygon
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rhombus
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Properties
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convex, isogonal, cyclic Opposite angles and sides are congruent
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Characterizations
Video: Understanding Quadrilaterals - Properties of Rectangles
A convex quadrilateral is a rectangle if and only if it is any one of the following:
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a parallelogram with at least one right angle
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a parallelogram with diagonals of equal length
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a parallelogram ABCD where triangles ABD and DCA are congruent
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an equiangular quadrilateral
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a quadrilateral with four right angles
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a convex quadrilateral with successive sides a, b, c, d whose area is .:fn.1
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a convex quadrilateral with successive sides a, b, c, d whose area is
.:fn.1
Classification
A rectangle is a special case of both parallelogram and trapezoid. A square is a special case of a rectangle.
Traditional hierarchy
A rectangle is a special case of a parallelogram in which each pair .....
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