Answer: You add up all the terms given of EACH angle, and make this an addition problem that is "equal to 180" ; since all triangles have three angles that add up to 180 degrees. Then you solve for "x".
__________________________________________________
(as follows) ; to get: " x = 29 ⅔ ° " .
_______________________________________
3x + 4 + 2x + x + 8 = 180 ;
_______________________________________
Combine the "like terms" ;
3x + 2x + x = 6x ;
4 + 8 = 12
So, we have: 6x + 12 = 180 ;
Now, subtract "12" from each side of the equation:
__________________________________________
6x + 12 − 12 = 180 − 12 ;
__________________________________________
to get:
6x = 178 ;
Now, divide EACH SIDE of the equation by "6" ; to isolate "x" on one side of the equation; and to solve for "x" ;
______________________________________
6x / 6 = 178 / 6 ;
to get: x = 178/6 = 29 ⅔ ° .
______________________________________
x = 29 ⅔ ° .
______________________________________
