D. Becaus it is the only one that mentions the characters of a triangle
12rocks 6 in each 2 equal piles
4 in each 3 equal piles And 3 in each 4 equal piles
When you arrange the N points in sequence around the polygon (clockwise or counterclockwise), the area is half the magnitude of the sum of the determinants of the points taken pairwise. The N determinants will also include the one involving the last point and the first one.
For example, consider the vertices of a triangle: (1,1), (2,3), (3,-1). Its area can be computed as
(1/2)*|(1*3-1*2) +(2*-1-3*3) +(3*1-(-1)*1)|
= (1/2)*|1 -11 +4| = 3
Everyone would be confused because they wouldnt know how to add. if there wasnt money then there with be no objects/food/toys/ect. unless its all free. If it all free then everyone would go crazy because they wouldnt have to calculate how much the item cost.