Question

Express cos A as a fraction in simplest terms.

Answer 1

Answer:

See below

Step-by-step explanation:

Here is one way

cos^2 + sin^2 = 1

cos^2 = 1 - sin^2  

For angle A      cos^2 = 1 - (10/26)^2

                          cos ^2 = 1 - 100/676

                                       =  576/676

                              cos A = 24/26   = 12/13

Another way would be to use the Pythagorean theorem to find length of AB .... then cos A =   length AB / 26