how to write algebraic verification of 4 sectors of the circle

Since this is not my area of expertise, I searched Google under the key words "algebraic verification of 4 sectors of the circle" to get these possible sources:

https://www.google.com/search?client=safari&rls=en&q=algebraic+verification+of+4+sectors+of+the+circle&ie=UTF-8&oe=UTF-8&gws_rd=ssl

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.