Heat (thermal) surface expansion of solid body
$$\Delta_{S} = 2\cdot \alpha\cdot S_{1}\cdot \Delta_{t}$$
Δ_S - change in area
α - temperature coefficient of linear expansion (linear expansivity)
S_1 - initial area
Δ_t - temperature change
α - temperature coefficient of linear expansion (linear expansivity)
S_1 - initial area
Δ_t - temperature change
Find
It is known that:
= 