Jawabanmu

2014-09-08T21:34:31+07:00
6/9=6+14/9+x
6/9=20/9+x
9+x=30
x=30-9
x=21
2014-09-08T21:36:39+07:00
DB = 9
DE = 14
BC = 20

AD/DE=AB/BC
AD/14=(AD+9)/20
20AD=14AD+126
7AD=126
AD= 126/7 = 18