Tolong beserta caranya yaa makasihh

AD = AC = 13cm
BD = CE = 12cm
AB = AE

kita cari panjang AB dulu
AB = √AD²-BD²
AB = √13²-12²
AB = √169-144
AB = √25
AB = 5cm

BC = AC-AB
BC = 13cm-5cm
BC = 8cm (D)