Using the formula
t = R−R0R(100)−R0×100∘C\frac{R - R_0}{R_{(100)} - R_0} \times 100^{\circ}\text{C}R(100)−R0R−R0×100∘C
t = 7.5−3.510.5−2..5×100∘C\frac{7.5 - 3.5}{10.5 - 2..5} \times 100^{\circ}\text{C}10.5−2..57.5−3.5×100∘C
= 47×100\frac{4}{7} \times 10074×100
= 57.14∘^{\circ}∘C
~ 57∘^{\circ}∘C
