Question 22. Martha chose one of the five structures below and combined it with the structure on the right. The table shows the number of cubes in each column in the combined structure when seen from above. Which of the five structures did Martha choose? To start off with, let's see how many cubes in each column we would see in the first structure. This will be 3, 2, 0, 0, 0, 2, 0, 0, 1. Now, let's lay out the number of cubes in each column for all of our potential answers. This will look like so. Now, to find our solution, let's take the sum of the cubes that is given in the answer and subtract each spot from the known structure. When we subtract each one like so, we'll get 0, 0, 3, 2, 1, 0, 1, 0, 0. And we see that this is one of our answers, so the answer will be D.

cubes

structure

columns

solution

Martha