Răspuns :
latura l =√ 8+ 3√2 cm =√4√2 + 3√2 = 2√2 +3√2 = 5√2 cm
perim. = 4 · l = 4· 5√2 cm =20√2cm
perim. = 4 · l = 4· 5√2 cm =20√2cm
[tex] P=4 l= \\ =4 ( \sqrt{8}+3 \sqrt{2} ) = \\ =4 \sqrt{8}+12 \sqrt{2}= \\ =4 \cdot 2 \sqrt{2}+12 \sqrt{2}= \\ =8 \sqrt{2}+12 \sqrt{2}= \\ =20 \sqrt{2}~~~~(cm).[/tex]