Răspuns :
cd=ad-ac
cd=15cm-10cm
cd=5cm
ab=ac-bc
ab=10cm-4cm
ab=6cm
bd=bc+cd
bd=4cm+5cm
bd=9cm
cd=15cm-10cm
cd=5cm
ab=ac-bc
ab=10cm-4cm
ab=6cm
bd=bc+cd
bd=4cm+5cm
bd=9cm