answer:We can rewrite the expression displaystylefrac{235^2-221^2}{14} as displaystylefrac{(235+221)(235-221)}{14}. Simplifying the numerator, we have displaystylefrac{(456)(14)}{14}. Cancelling the common factor of 14, we are left with boxed{456}. The answer is: 456

answer:If 30% of the community members were adult men, then there were 2000 * 0.30 = 600 adult men involved in the cleaning event. Since there were twice as many adult women as men, there were 600 * 2 = 1200 adult women involved in the cleaning event. Therefore, the total number of adult men and women involved in the cleaning event is 600 + 1200 = 1800. To find the number of children involved, we subtract the number of adults from the total number of community members: 2000 - 1800 = 200. So, there were 200 children involved in the cleaning event. 200 The answer is: 200

answer:We know that the sum of all angles in a triangle is 180 degrees. We are given that angle A is 60 degrees. We are also given that angle B is two times as big as angle C. Let's say angle C is x degrees. So, angle B is 2x degrees. The sum of angles A, B, and C is 60 + 2x + x = 180. Combining like terms, we get 3x + 60 = 180. Subtracting 60 from both sides, we get 3x = 120. Dividing both sides by 3, we get x = 40. Therefore, angle C is 40 degrees. Since angle B is two times as big as angle C, angle B is 2 * 40 = 80 degrees. 80 The answer is: 80

answer:Since overline{DC} is parallel to overline{AB}, we have angle DCA = angle ABC. Therefore, angle ACB = 180^circ - angle DCA - angle ABC = 180^circ - 40^circ - 73^circ = boxed{67^circ}. The answer is: 67