tolong gengs bantu jwb yg bisa, mksh

4/AB=3/12
3AB=12 x 4
AB =(12x4) : 3
AB =48:3
=16

cari CD dulu
CD = akar DE^2+CE^2
CD = akar 4^2+3^2
CD = akar 16+9
CD = akar 25
CD = 5

CD / CA = CE/ BC
5 / CA = 3/12
CA = 12x5/3
CA = 60/3
CA = 20

CA ^2 = AB^2+BC^2
AB^2 = CA^2-BC^2
AB = akar 20^2-12^2
AB = akar 400-144
AB = akar 256
AB = 16 m