\( 2(1+\sqrt{2}) 70^{2} \)
\( 9800 + 13856\sqrt{2} \)
Step 1 :\( 2(1+\sqrt{2}) 70^{2} \)
Step 2 :\( 2(1+\sqrt{2}) \times 4900 \)
Step 3 :\( 9800 + 13856\sqrt{2} \)