Answer:
54
Step-by-step explanation:
The sum of two interior angles in a triangle is equal to an exterior angle that is supplementary to the third interior angle:
30 + 10x + 12 = 15x + 7 add like terms
10x + 42 = 15x + 7 export like terms to the same side of the equation
42 - 7 = 15x - 10x
35 = 5x divide both sides by 5
7 = x now to calculate the value of angle G replace x with 7
10x + 12 = 10*7 + 12
<G = 54
