Tolong Bantu Jawab Ya dengan Baik dan Benar + Terutama Caranya…

8.HF:DF = 12:4=3:1
GH :DF= x : 5 = 3 : 1
(5×3) : (5×1)
15 : 5 = 3 : 1
GF :FE = x : 7 = 3 : 1
(7x 3) :(7×1)
21 : 7 = 3 :1

7.DC/AC =DE/AB
10/X =8/12
kali silang
8X = 10 x12
X = 120/8
X = 15
jadi AC = 15