Jawabanmu

2014-05-11T17:37:00+07:00
S = 30 + 40 + 50 / 2 = 60

60-30 = 30
60-40 = 20
60-50 = 10
R = 30 * 40 * 50 / 4 * √60 * 30 * 20 *10
    = 30 * 40 * 50 / 4 * √360000
    = 30 * 40 * 50 / 4 * 600
    = 60000 / 2400 = 25 cm
4 3 4