1 / 6

The Law of Cosines

The Law of Cosines . Emily Liu Per 2. Law Of Cosines: a^2 = b^2+c^2-2bc( cosA ) b^2= a^2+ c^2- 2ac ( cosB ) c^2= a^2 +b^ 2- 2ab( cosC ). Formulas for Law of Cosines . Use Law of Cosines when.. The triangle given has two sides and the included angle

ollie
Download Presentation

The Law of Cosines

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Law of Cosines Emily Liu Per 2

  2. Law Of Cosines: a^2 = b^2+c^2-2bc(cosA) b^2= a^2+c^2-2ac(cosB) c^2= a^2+b^2-2ab(cosC) Formulas for Law of Cosines

  3. Use Law of Cosines when.. • The triangle given has two sides and the included angle • The triangle given has three sides When to use law of cosines

  4. Example: Find a 1) Use the formula: a^2 = b^2+c^2-2bc(cosA) 2) a^2= 21^2+42^2-2*21*42(cos 39) 3) a= 28.9

  5. Example: Find Z * Although the formulas given may not have the variables x, y, or z, the same concepts apply. z^2 = x^2+y^2-2xy (cos Z) 4^2 =7^2+10^2-2*10*7 ( cos Z) Z= 18.2 degrees

  6. You can also apply your knowledge of Law of Cosines to other concepts like area. Find the area Area= ½ zxsinY ( use law of cosines to figure out Y) y^2= z^2+ x^2 -2*x*z (cos Y) 10^2=4^2+7^2-2*4*7 (cos Y) Y= 128.7 degrees use area formula ½ 4*7* sin (128.7) area= 11.0

More Related