The answer is 12. My explanations is that LCM is the smallest number that both numbers can fit into. 12 fits into 12 once, and 4 fits into 12 3 times, so 12 is the answer.
I belive the answer to be b
The net would look like a square surrounded with four triangles, one on each side.
Answer: Choice C) Same-side interior angles
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Angle 4 and angle 6 are on the same side, in this case the right hand side of the transversal line (line t). In addition, they are on the interior of the "train tracks" horizontal lines (line a and line b). Combine this and this is why the two angles are same-side interior angles
Side note: if line a is parallel to line b, then angle 4 and angle 6 add to 180 degrees. At this point, they are considered supplementary.