5x= one angle measure
7x= second angle measure
120°= third angle
Triangles equal 180°. Add the angles above to total 180°. Find x to find two two unknown angles.
5x + 7x + 120°= 180°
combine like values
12x + 120= 180
subtract 120 from both sides
12x= 60
divide both sides by 12
x= 5
ONE ANGLE MEASURE
5x= 5(5)= 25°
SECOND ANGLE MEASURE
7x= 7(5)= 35°
CHECK:
25° + 35° + 120°= 180°
180°= 180°
ANSWER: The measures of the two angles are 25° and 35°.
Hope this helps! :)