# Inclination

Pronunciation: /ˌɪn.kləˈneɪ.ʃən/ Explain

 Click on the blue points and drag it to change the figure Manipulative 1 - Inclination Created with GeoGebra.

An inclination is the angle between a reference line or plane and another line or plane. In manipulative 1, the inclination of the line is respective to the x-axis. Note that the inclination is measured with an angle between and 90° (0° < α ≤ 90°).

An incline is a surface that is sloped relative to the horizontal.

 Click on the blue point and drag it to change the figure. Manipulative 2 - Inclination of an Orbit Created with GeoGebra.

An inclined plane is a plane that is sloped relative to a reference plane. For astronomical objects, the reference plane contains the equator of the object about which another object orbits.

In manipulative 2, the blue ellipse represents a plane containing the equator of a star. The red ellipse represents a plane containing the orbit of a planet.

### References

1. McAdams, David E.. All Math Words Dictionary, inclination. 2nd Classroom edition 20150108-4799968. pg 95. Life is a Story Problem LLC. January 8, 2015. Buy the book
2. Alessandra Celletti, Ettore Perozzi. Celestial Mechanics: The Waltz of the Planets. pg 9. Springer. January 24, 2007. Last Accessed 8/7/2018. Buy the book
3. Michael D. Griffin, James R. French. Space Vehicle Design. 2nd edition. pp 20-22. American Institute of Aeronautics & Astrophysics. March 2004. Last Accessed 8/7/2018. Buy the book

McAdams, David E. Inclination. 4/23/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/i/inclination.html.

### Revision History

4/23/2019: Updated equations and expressions to new format. (McAdams, David E.)