Jawabanmu

2014-02-19T20:36:54+07:00
L s = 1/2 8 X 15
= 60
a. 2s = 8 + 15 + 17         r = L/s =60/20 = 3    
        s = 40/2 = 20   
L = 3.14 X 3² = 28.26
2 4 2