Jawabanmu

2014-02-13T05:35:54+07:00
 \frac{Pb AB}{Pb CD} =  \frac{sudut AOB}{sudut COD} \\ \frac{40}{CD} =  \frac{50}{80}
 CD = 40.80 / 50
 CD = 64 cm
Gud Luck !
jadikan yg terbaik ya :D