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parallelogram
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A grid displays a green rectangle, a red parallelogram, and a purple triangle, each labeled with base and height dimensions. Area formulas are shown: rectangle and parallelogram as base times height, triangle as one-half base times height. Figure 11: Construction for the dissection of parallelograms (see text). Figure 13: Constructions for the equivalence by dissection of (left) squares and (right) parallelograms (see text). Figure 12: Construction for the proof of equivalency of parallelograms by dissection (see text). vector parallelogram for addition and subtraction
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A grid displays a green rectangle, a red parallelogram, and a purple triangle, each labeled with base and height dimensions. Area formulas are shown: rectangle and parallelogram as base times height, triangle as one-half base times height.
formulas for calculating the area of parallelograms and triangles A rectangle, a parallelogram, and a triangle with their formulas to determine the area for each shape. The grid shows that the three figures have the same area.

parallelogram

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Melissa Petruzzello
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parallelogram, in geometry, a four-sided plane figure in which both pairs of opposite sides are parallel and equal.

A parallelogram is a quadrilateral (a polygon with four sides) in which the opposite angles are equal and the diagonals bisect each other. Bisecting a parallelogram along a diagonal divides the figure into two congruent triangles.

Rectangles, rhombuses, and squares are all special types of parallelograms. A rectangle is an equiangular parallelogram (all four angles are equal), a rhombus is an equilateral parallelogram (all four sides are equal), and a square is a parallelogram that is both equiangular and equilateral.

Parallelograms are often used in physics and other fields to graphically add or subtract vectors.

Melissa Petruzzello