1. The problem involves comparing three triangles: $\triangle ABC$, $\triangle DEF$, and $\triangle GHI$ with given side lengths. 2. We want to determine which triangle is similar to $\triangle ABC$ by checking if the ratios of corresponding sides are equal. 3. The sides of $\triangle ABC$ are 6, 7, and 7. 4. For $\triangle DEF$, the sides are 0.7, 0.7, and 0.6. 5. For $\triangle GHI$, the sides are 3, 3.5, and 3.5. 6. Calculate the ratios of sides of $\triangle DEF$ to $\triangle ABC$: $$\frac{0.7}{6} = 0.1167, \quad \frac{0.7}{7} = 0.1, \quad \frac{0.6}{7} = 0.0857$$ These are not equal, so $\triangle DEF$ is not similar to $\triangle ABC$. 7. Calculate the ratios of sides of $\triangle GHI$ to $\triangle ABC$: $$\frac{3}{6} = 0.5, \quad \frac{3.5}{7} = 0.5, \quad \frac{3.5}{7} = 0.5$$ All ratios are equal, so $\triangle GHI$ is similar to $\triangle ABC$. 8. Therefore, the correct answer is $\triangle GHI$.