tolong dijawab mau un soalnya

Misal , lebar sungai = x.
Misal , titik yg pling atas = O

OD / OA = DC / AB
x / (4 + x) = 6/8
x / (4+x) = 3/4
(4+x) . 3 = 4x
12 + 3x = 4x
12 = 4x - 3x
x = 12 cm (lebar sungai) --> (b.)

pohon = p

DP/DC = AD+DP/AB
x/6 = 4+x/8   (kali silang)
8x = 24 + 6x
8x-6x = 24
2x=24
x=12

DP=x=12 m