tolong bantu 2 soal aja ya. makasih sebelumnya

4.
segitiga ABC
12 : 8 : 6 = 6 : 4 : 3

segitiga PQR
x : 12 : 9

x/6 = 9/3
x = 6 x 3
x = 18 cm
jawaban B

5.
(10 + x)/20 = 8/12
10 + x = 8/12 x 20
10 + x = 13 1/3
x = 13 1/3 - 10
x = 3 1/3

jawaban D