26 lines
1.3 KiB
Markdown
26 lines
1.3 KiB
Markdown
|
---
|
||
|
|
title: Law of Cosines
|
||
|
|
---
|
||
|
|
## Law of Cosines
|
||
|
|
|
||
|
|
The Law of Cosines can be used to find the ramaining sides or angles of a non-right triangle when given either the length of two sides and its included angle (SAS) or the lengths of the three sides (SSS).
|
||
|
|
The Law of Cosines states:
|
||
|
|
<img src="http://hyperphysics.phy-astr.gsu.edu/hbase/imgmth/lcos.gif">
|
||
|
|
|
||
|
|
This looks very similar to the Pythagorean Theorem, and if C was 90 degrees (a right triange), the expression acctually simplifies to the Pythagorean Thoerem. So, the Pythagorean Theorem is a special case of the Law of Cosines.
|
||
|
|
|
||
|
|
You can also switch the angle C with either A or B, but make sure to change the respective side (c) to a or b.
|
||
|
|
|
||
|
|
<img src="http://www.mathwarehouse.com/trigonometry/images/law-of-cosines/law-of-cosines-formula-and-picture2.png">
|
||
|
|
|
||
|
|
Ex:
|
||
|
|
|
||
|
|
<img src="http://www.mathwarehouse.com/sheets/trigonometry/advanced/law-of-sines-and-cosines/images/picture-of-law-of-cosines.png">
|
||
|
|
<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds -->
|
||
|
|
|
||
|
|
#### More Information:
|
||
|
|
<!-- Please add any articles you think might be helpful to read before writing the article -->
|
||
|
|
https://www.varsitytutors.com/hotmath/hotmath_help/topics/law-of-cosines
|
||
|
|
http://mathworld.wolfram.com/LawofCosines.html
|
||
|
|
|