Problem 6
Answer: Choice B) Angle NMS and angle MNT
These two angles are the base angles of isosceles trapezoid MSTN. The congruent base angles are opposite the congruent legs.
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Problem 7
I'm assuming they mean "interior angle"
If so, then E = 360/n = 360/16 = 22.5 is the measure of each exterior angle
So 180-E = 180-22.5 = 157.5 is the measure of each interior angle
Answer: 157.5 degrees