Jawabanmu

2014-06-03T10:02:35+07:00
Misal : RS = x
L =  1/2 * (jumlah sisi sejajar) * t
150 = 1/2 * (18+x) * 10
150 = 5 (18+x)
150 = 90 + 5x
60 = 5x
12 = x
Jadi, panjang RS = 12 cm