Answer:
The exterior angles need to equal 360 degrees.
You have 70 + 65 + 75 = 210
So 2x + 3x need to equal 360 - 210 = 150
5x = 150
x = 150 /5 = 30
2x = 2 *30 = 60
3x = x *30 = 90
An interior angle and an exterior angle need to equal 180 degrees.
The largest interior angle would need to correspond with the smallest exterior angle.
The smallest exterior angle is 2x which equals 60 degrees.
The largest interior angle would be 180 - 60 = 120 degrees.
