Circumscribe

Pronunciation: /ˈsɜr kəmˌskraɪb/ Explain

Click on the blue points and drag them to change the figure.

Try to change the figure so that the circumcenter is outside of the triangle. For what type of triangle does this happen.
Manipulative 1 - Circumscribed Triangle Created with GeoGebra.

To circumscribe is to draw a circle around a 2-dimensional object or a sphere around a 3-dimensional object that intersects all the vertices of the figure, but does not intersect any side.[1] A geometric figure is circumscribable if a circle can be drawn that intersects all the vertices of the figure, but not does not intersect any side.
See Circumscribing a Circle About a Triangle.

To inscribe is to draw a circle or sphere that is completely inside another figure that intersects each side of the figure exactly once.[2]
See Inscribing a Circle in a Triangle. A geometric figure is inscribable if a circle can be drawn that intersects each side exactly once.

To use the manipulatives, click on the blue points and drag them. This will change the figures.

Click on the blue points and drag them to change the figure.

Can the incenter (point D) be outside the triangle? How do you know.
Manipulative 2 - Inscribed Triangle Created with GeoGebra.

How To

How to circumscribe a triangle with a circle.
How to circumscribe a rectangle with a circle.
How to inscribe a circle in a triangle.

References

  1. Sampson, Charles H.. Mechanical Drawing and Practical Drafting. pg 10. www.archive.org. Milton Bradley Company. 1920. Last Accessed 8/6/2018. http://www.archive.org/stream/mechanicaldrawin00samprich#page/10/mode/1up/search/circumscribe. Buy the book

Cite this article as:

McAdams, David E. Circumscribe. 6/25/2018. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/c/circumscribe.html.

Image Credits

Revision History

6/25/2018: Removed broken links, updated license, implemented new markup, updated GeoGebra apps. (McAdams, David E.)
1/11/2010: Added "References". (McAdams, David E.)
11/27/2008: Added definitions for circumscribable and inscribable. (McAdams, David E.)
7/1/2008: Changed figures to use GeoGebra. Added "how to" (McAdams, David E.)
6/7/2008: Corrected spelling. (McAdams, David E.)
4/23/2008: Initial version. (McAdams, David E.)

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