Use the image to answer the question.

Question

An illustration shows three grids with boxes shaded in an X pattern inside. The first is a 6 by 6 grid labeled as term 1, the second is an 8 by 8 grid labeled as term 2, and the third is a 10 by 10 grid labeled as term 3. In all the grids, the diagonal boxes extending from the corners to the center are shaded. In term 1, 12 boxes are shaded, in term 2, 16 boxes are shaded, and in term 3, 20 boxes are shaded.

What are the first three terms of the arithmetic sequence represented by the number of shaded tiles and the common difference?

(2 points)
The first three terms are
,
, and
, and the common difference is
.

Answer 1

The first three terms are 12, 16, and 20, and the common difference is 4.