Hitunglah nilai a,b,c dan d pada gambar berikut MOHON BANTUANNYA BESERTA CARA JALANNYA

Aku bantu tiga aja ya

(a.)
4/a = 6/9
4/a=2/3
2/a = 1/3
a=6 cm

(b.)
8/12 = b/(b + 4)
2/3 = b/(b + 4)
3b = 2b + 8
b=8 cm

(c.)
6/9 = 8/(8 + c)
2/3 = 8/(8 + c)
1/3 = 4/(8 + c)
12 = 8 + c
c = 4 cm