Divide the nonagon radially into 9 congruent, equilateral isosceles triangle. Each triangle has vertex angle of 360°/9 = 40°.
Interior angle of polygon = 180°-40° = 140°.
Sum of interior angles = 9(140°) = 1260°
Your answer is B because it’s 6 times 3 times 4 and you add cubic because it’s volume.
The group of seventh graders will have 5 groups of five: 5 is the greatest multiple of 25, or 5*5=25. Then for the sixth graders there will be 4 groups of 5: because 4&5 are the greatest factors of 20 and you want the most amount of kids per group, you would have 5 kids in each group. Hope this helps.
