cosines
posted by Anon .
I don't know how to reverse cosine decimals into angles. Can you please explain and help me solve these .
cos A= 0.28571428571
A=
cos B= 0.66666666667
B=
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^{1}A is 81.7867893°.