Neste Caso usaremos o coeficiente de dilatação superficial beta = 2alpha
beta = 2 * 1,2 *10^-5°C^-1
****************************
beta = 2,4 * 10^-5°C^-1
****************************
So = 20*30 = 600cm²
/\S = So * beta * /\T
/\S = 600 * 2,4*10^-5 * 150
/\S = 6 * 2,4 * 10^-3 * 150
/\S = 2160 * 10^-3
**********************************
/\S = 2,16cm² de Variação
**********************************
/\S = S - So
2,16 = S - 600
S = 2,16 + 600
********************
S = 602,16cm²
********************