Tolong kerjakan nomor 24 ya

ΔBFE sebangun dgn ΔBDA
mk BE/BA = EF/AD
20/30 = 18/AD
AD = 27 cm

ΔDAF kongruen dgn ΔCBF (su, si, su)
krn sudut ADF = sdt BCF (diket)
FD = FC ( diket)
sdt DFA = sdt CFB (bertolak blkg)
Maka BC=AD=27 cm