en.wikipedia.org/wiki/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 ...

www.mathsisfun.com/geometry/rectangle.html

Rectangle. (Jump to Area of a Rectangle or Perimeter of a Rectangle). A
rectangle is a four-sided flat shape where every angle is a right angle (90°).

quatr.us/math/geometry/rectangle.htm

Nov 28, 2016 ... November 2016 - A rectangle is a flat shape, in one plane, defined by four points
at the four corners. A rectangle has two sides of equal length ...

www.mathopenref.com/rectangle.html

The rectangle, like the square, is one of the most commonly known quadrilaterals
. It is defined as having all four interior angles 90° (right angles).

docs.oracle.com/javase/8/docs/api/java/awt/Rectangle.html

A Rectangle specifies an area in a coordinate space that is enclosed by the
Rectangle object's upper-left point (x,y) in the coordinate space, its width, and its
...

www.coolmath.com/reference/rectangles

Definitions and formulas for the perimeter of a rectangle, the area of a rectangle,
how to find the length of the diagonal of a rectangle, properties of the diagonals ...

www.merriam-webster.com/dictionary/rectangle

a parallelogram all of whose angles are right angles; especially : one with
adjacent sides of unequal length. See rectangle defined for English-language ...

mathworld.wolfram.com/Rectangle.html

Rectangle. DOWNLOAD Mathematica Notebook EXPLORE THIS TOPIC IN the
MathWorld Classroom Rectangle. A closed planar quadrilateral with opposite ...

reference.wolfram.com/language/ref/Rectangle.html

Rectangle[{xmin, ymin}, {xmax, ymax}] represents an axis-aligned filled rectangle
from {xmin, ymin} to {xmax, ymax}. Rectangle[{xmin, ymin}] corresponds to a ...

doc.qt.io/qt-5/qml-qtquick-rectangle.html

Each Rectangle item is painted using either a solid fill color, specified using the
color property, or a gradient, defined using a Gradient type and set using the ...