Answer:
Let coefficient of linear and area expansion be α a n d β respectively. where ∆ T is change in temperature. For simplicity let us consider the case of square of side L. Therefore, coefficient of area expansion is twice the linear expansion.
I would say by using a telescope to look into the sky
I believe its the Ottomans or something like that but I am not 100% sure. Please tell me if you know the right answer.
