Convert $50 {\mathrm{cm}}^2 \mathrm{in} {\mathrm{mm}}^2$

 $50 {\mathrm{cm}}^2 =50 {\left(\mathrm{cm}\right)}^2$  (We know that 1 cm = 10 mm)

$={50 (10 \mathrm{mm})}^2=50\times 10\mathrm{mm} \times 10 \mathrm{mm}$

$=5000 {\mathrm{mm}}^2$

Therefore, $50 {\mathrm{cm}}^2 = 5000 {\mathrm{mm}}^2$.