Question

Tolong kerjaiin dong nom 13 please

Answer 1

ADB = siku-siku ya
jadi cari dulu panjang BD
20 kuadrat - 16 kuadrat = 400 - 256 = 144 -> 12 cm

intinya segitiga ABC sebangun dgn segitiga ABD.
kita buat deh perbandingannya

AB / BC = AD / BD
20 / BC = 16 / 12
rasio perbandingannya jadinya 4 : 3

jadi:
20 / BC = 4 / 3
4 BC = 60 (kali silang)
BC = 15 cm

sekarang tinggal cari CD
15 kuadrat + 20 kuadrat = AC kuadrat
225 + 400 = AC kuadrat
625 = AC kuadrat
AC = 25 cm

AC = 25, AD = 16, DC = 25 - 16 = 9 cm

Luas BCD = 1/2 x BD x CD = 1/2 x 12 x 9 = 1/2 x 108 = 54 cm2