Jawabanmu

2014-05-11T20:53:09+07:00
L = (jumlah sisi sejajar) x tinggi : 2
150 = (18+x) x 10 ; 2
150 =(18+x) x 5
150:5 = 18+x
30 = 18 +x
30-18 = x
12 = x
2014-05-11T21:44:28+07:00
Luas trapesium = (SR+PQ) x ST : 2
⇒150 = (SR + 18) x 10 : 2
⇒150 x 2 = 10xSR + 180
⇒10xSR = 300 - 180
⇒SR = 120 : 10 = 12 cm