Answer:
18
Step-by-step explanation:
Volume is a product of cross-sectional area and height and relresented as V=Ah where V is volume, A is cross-sectional area and h is height.
For the square, since each has a thickness of 6mm then for 24 of them the height will be 24*6=144 mm
Since the volume and cross sectional area of the triangle should be the same, then the height should also be the same.
Since for the triangle each has a thickness of 8mm then the number requred to achieve a height of 144 mm will be 144/8=18 stacks