Search results
Results from the WOW.Com Content Network
In mathematics, the simplest form of the parallelogram law (also called the parallelogram identity) belongs to elementary geometry. It states that the sum of the squares of the lengths of the four sides of a parallelogram equals the sum of the squares of the lengths of the two diagonals.
Rectangle – A parallelogram with four angles of equal size (right angles). Rhombus – A parallelogram with four sides of equal length. Any parallelogram that is neither a rectangle nor a rhombus was traditionally called a rhomboid but this term is not used in modern mathematics. [1] Square – A parallelogram with four sides of equal length ...
Rhomboid: a parallelogram in which adjacent sides are of unequal lengths, and some angles are oblique (equiv., having no right angles). Informally: "a pushed-over oblong". Not all references agree; some define a rhomboid as a parallelogram that is not a rhombus. [4] Rectangle: all four angles are right angles (equiangular). An equivalent ...
The first property implies that every rhombus is a parallelogram. A rhombus therefore has all of the properties of a parallelogram: for example, opposite sides are parallel; adjacent angles are supplementary; the two diagonals bisect one another; any line through the midpoint bisects the area; and the sum of the squares of the sides equals the ...
The sum of the distances from any interior point of a parallelogram to the sides is independent of the location of the point. The converse also holds: If the sum of the distances from a point in the interior of a quadrilateral to the sides is independent of the location of the point, then the quadrilateral is a parallelogram. [3]
Since the sum of the angles of a triangle is equal to 180°, we have ... the parallelogram must be a rectangle. All angles in a rectangle are right angles. ...
An angle is defined by its measure and is not dependent upon the lengths of the sides of the angle (e.g., all right angles are equal in measure). Two angles that share terminal sides, but differ in size by an integer multiple of a turn, are called coterminal angles.
Parallelogram law – Sum of the squares of all 4 sides of a parallelogram equals that of the 2 diagonals; Polarization identity – Formula relating the norm and the inner product in a inner product space; Ptolemy – Roman astronomer and geographer (c. 100–170) Ptolemy's table of chords – 2nd century AD trigonometric table