Răspuns:
Explicație pas cu pas:
[tex]\frac{OA}{OC} =\frac{OB}{OD} =\frac{72}{32} \\\frac{OA}{OC} =\frac{OB}{OD} =\frac{9}{4} \\[/tex]
[tex]\frac{OA}{OC} =\frac{9}{4}[/tex]
[tex]\frac{OA+OC}{OC} =\frac{9+4}{4}[/tex]
[tex]\frac{CA}{OC} =\frac{13}{4} \\[/tex]
[tex]\frac{65}{OC} =\frac{13}{4} \\[/tex]
OC=20 ⇒ OA=65-20=45
[tex]\frac{OB}{OD} =\frac{9}{4}[/tex]
[tex]\frac{OB+OD}{OD} =\frac{9+4}{4}[/tex]
[tex]\frac{BD}{OD} =\frac{13}{4}[/tex]
[tex]\frac{78}{OD} =\frac{13}{4}[/tex]
OD=24 ⇒OB=78-24=54