In a ∆ABC, if ∠C = 60°, a = 47 cm and b = 94 cm,

Given ∠C = 60∘ , a = 47 , b = 94  In  ∆ABC

Using $\cos C=\frac{a^{2}+b^{2}-c^{2}}{2 a b}$

i.e $\cos 60^{\circ}=\frac{(47)^{2}+(94)^{2}-C^{2}}{2 \times 47 \times 94}$

i.e $2 \times \frac{1}{2} \times 47 \times 94=(47)^{2}+(94)^{2}-C^{2}$

i.e $C^{2}=(47)^{2}+(94)^{2}-47 \times 47 \times 2$

$=-(47)^{2}+(94)^{2}$

$\therefore C^{2}=8836-22049=6627$