I hope this helps you
3.2x-3.4+4x-2
6x-12+4x-2
10x-14
Thr answer is False
That line is called diameter
As the exterior angles always add up to 360, you can find the number of sides by dividing 360 by the measure of your exterior angle, 30. This gives you 360/30=12, meaning your polygon has 12 sides.