Facts About Parallelograms

Colorful diamond pattern
••• AndreaAstes/iStock/Getty Images

A parallelogram is a two-dimensional quadrilateral -- a shape that has four sides that intersect at four points, also known as vertices. The two opposite sides of a parallelogram are always parallel and congruent -- or equal in length. Rectangles, squares and rhombuses are all examples of parallelograms.

Opposite Sides

Both pairs of opposite sides of a parallelogram are always parallel, and both pairs of opposite sides of a parallelogram are always congruent. You can find the distance around a parallelogram, also known as the perimeter, by measuring and adding the length of the four sides together. Because opposite sides of a parallelogram are parallel, they will never intersect.

Diagonal Lines

The diagonals of a parallelogram -- lines that extend from one corner to the opposite corner -- bisect one another. In other words, each diagonal cuts its opposite diagonal into two equal parts. No matter how you reshape a parallelogram, such as making the sides shorter or longer or increasing and decreasing the height, the diagonals will always bisect one another.

Area of a Parallelogram

Calculate the area of a parallelogram by multiplying the base by the altitude, also known as the height. You can use any side of a parallelogram as the base. The altitude is the perpendicular distance from the base to the opposite side. In some cases, you may need to extend the opposite side of the parallelogram to be able to find and measure the perpendicular distance.

Interior Angles

Opposite interior angles of a parallelogram are always equal. For example, if one interior angle measures 36 degrees, the opposite interior angle will also measure 36 degrees. Consecutive interior angles in a parallelogram -- angles that are side by side -- are supplementary. That means that when you add two interior consecutive angles together, the total always equals 180 degrees. When you add all four interior angles together, the total always equals 360 degrees.

Quadrilateral Midpoints

When you locate the midpoints -- the middle of the line segment or the halfway point -- on each side of a quadrilateral and connect those points with consecutive straight lines, the result is always a parallelogram.

Specific Geometric Shapes

Rectangles and squares are examples of parallelograms that have 90 degree angles, also known as right angles. Rhombuses and squares are examples of parallelograms that have sides of equal length.

Related Articles

How to Find the Perimeter of a Six-Sided Figure
How to Find the Height of a Rhombus
How to Find Angles in a Trapezoid
How to Calculate the Perimeter of Quadrilaterals
How to Find Angles & Sides of a Triangle
How to Find an Angle of a Hexagon
How to Find the Area of a Rectangular Prism
How to Find the Area of Triangles & Trapezoids
Six Properties of a Parallelogram
How to Get the Lateral Area of a Pentagonal Pyramid
How to Find the Lateral Area of a Square Pyramid
How to Solve a Hexagon
How to Identify X in Angles in Geometry
How to Find the Volume of a Parallelogram
Rules for Creating Tessellations
What Are Congruent Shapes?
How to Calculate the Sum of the Exterior Angles of...
How to Find the Number of Sides of a Polygon
How to Find the Surface Area of a Triangular Prism
How to Find the Surface Area of a Triangular Prism...

Dont Go!

We Have More Great Sciencing Articles!