Jawabanmu

2014-06-03T09:53:59+07:00
AB = 4
TA = 8
Tinggi sis tegak = TP = 2√15
cos alpa = 2TP² - AB² / 2.TP² = 2(60) - 16 / 2.60 = 104/120 = 13/15
Jawaban: 13/15