Soal sbm tolong dijawab cepat nomor 4 yaa.

Pencerminan terhadap x = a

…………x=a
(s, t) ———-> (2a – s, t)

pencerminan terhadap y = b

…………………y=b
(2a – s, t) —————> (2a – s, 2b – t)

garis melalui (s, t) dan (2a – s, 2b – t)

persamaan garis =
(y – y1)/(y2 – y1) = (x – x1)/(x2 – x1)
(y – t)/ (2b – t – t) = (x – s)/(2a – s – s)
(y – t)/(2b – 2t) = (x – s)/(2a – 2s)

garis melalui (0, 0)
(0 – t)/(2b – 2t) = (0 – s)/(2a – 2s)
-t/(2b – 2t) = -s/(2a – 2s)
-t(2a – 2s) = -s(2b – 2t)
-2at + 2st = -2bs + 2st
-2at + 2bs = 2st – 2st
-2at + 2bs = 0
2at = 2bs
a/b = 2s/2t
a/b = s/t
a : b = s : t

= A.