# plane geometry

- the geometry of figures whose parts all lie in one plane.

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## Origin of plane geometry^{}

First recorded in 1740–50

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

## plane geometry

- the study of the properties of and relationships between plane curves, figures, etc

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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## plane geometry

- The mathematical study of geometric figures whose parts lie in the same plane, such as polygons, circles, and lines.

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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

## plane geometry

The study of two-dimensional figures (figures that are confined to a plane).

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## Note

Plane geometry is one of the oldest branches of mathematics.

## Note

The Greek mathematician Euclid was the first to study plane geometry carefully. His book Elements was the standard plane geometry textbook for centuries.

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.