This problem could be extended to find the number of tiles needed for the 10th, 100th, and then the nth term. Ask students to describe how to build each term. Look for answers that relate each term to the previous term, and then relate the figure to its place in the pattern. For example, students might notice that the 1st term uses 1 tile, the 2nd term uses 1 + 2, or 3 tiles, the 3rd term uses 1 + 2 + 3, or 6 tiles, and so forth. The nth term uses 1 + 2 + 3 + ... + n tiles.