so for A it is 16 times as large because the area is 3*3 which is 9 but since it is a triangle the area is halved and is 4.5 and divide 72 by 4.5 which gives us 16
then for b I believe that the scale factor is 4
and for C it is asking for the bottom side of the scaled copy not of triangle A and 4*3=12 so the bottom is 12
