tolong jawab no 18,19,dan21 dengan cara ya kakak plissss ^_^

18.) 3/4 x 140 cm = 105 cm (c.)
19.) 6 x 1/3 = 2
6-2=3 (b.)
20.) jp = jarak peta
js = jarak sebenarnya
s = skala

jp = s x js
= 1/400 x 1000cm
= 2,5 cm
jp = s x js
= 1/400 x 800cm
= 2cm
jadi, panjang = 2,5 cm
lebar = 2 cm (b.)