All three angles in a triangle have a sum of 180°. To solve this problem, simply set up an algebra equation:
[tex]c + c + 68 = 180[/tex] ---> [tex]2c + 68 = 180[/tex]
Isolate the variable:
[tex]2c + 68 - 68 = 180 - 68[/tex]
--> [tex]2c = 112[/tex]
Isolate again:
[tex]\frac{2c}{2} = \frac{112}{2}[/tex]
--> [tex]c = 56[/tex]
Check your work:
[tex]2(56) + 68[/tex]
--> [tex]112 + 68 = 180[/tex]
So now you know for sure that c = 56.
