[tex]A_{romb}=\frac{d_1*d_2}{2}\;daca\;d_1=18\;atunci,\\
avem:\;\;\frac{18*d_2}{2}=216\;de\;unde\;\rightarrow\;d_2=24\;;\\
fie\,\,d_1\cap{d_2}=\{O\}\;;\;\Rightarrow\;\Delta_{AOB}-dreptunghic\;\\
deci AB^2=(18/2)^2+(24/2)^2=225\;deci\;AB=15cm\\
\Rightarrow\;P_{rombb}=4*15cm=60cm\;; [/tex]