tolong dibantu no30 kak

diketahui:
BD = 4cm
AD = 3cm

ditanya:
BC

dijawab:
kita cari panjang CD dulu, make perbandingan

BD/AD = AD/CD
4/3 = 3/CD
CD = 3×3 / 4
CD = 2,25cm

BC = BD+CD
BC = 4cm + 2,25cm
BC = 6,25cm (B)