If PQ × PR =4 i +8 j -8 k, then the area ( PQR ) is

If $\displaystyle \overrightarrow{\mathrm{PQ}} \times \overrightarrow{\mathrm{PR}}=4 \hat{\mathrm{i}}+8 \hat{\mathrm{j}}-8 \hat{\mathrm{k}}$, then the area ( $\displaystyle \triangle \mathrm{PQR}$ ) is