posted by Anon on .
I don't know how to reverse cosine decimals into angles. Can you please explain and help me solve these .
cos A= 0.28571428571
cos B= 0.66666666667
cos C= 0.5238089523
If you use a calculator, it would be the cos-1 key.
Depending on the calculator, you would enter the cos value (e.g. 0.2857142857) and press the cos-1 key. Some calculators require the cos-1 key to be pressed first followed by the value.
If you do not use a calculator, let me know what you use, a table of cosines, or something else.
For example, cos-1A is 81.7867893°.