1. The problem statement, all variables and given/known data This is a question from my physics book, i don't understand its solution. Consider a square hole in an aluminum plate (2D) . If this block is heated, will this hole become smaller or larger ? 2. Relevant equations δL/L = β*δT 3. The attempt at a solution As each of the side of the block expands (some a lttle, while the longer sides more) thus the area decreases. But, the answer as given by the book is that the area would increase. Can anyone help me understand this ?