Jawabanmu

2014-02-26T21:34:54+07:00
K persegi = 4s = 4.5x = 20x
k = 2(p+l)
20x = 2((6x + 10)+(2x + 20))
20x = 2(8x + 30)
20x = 16x + 60
20x - 16x = 60
4x = 60
x =  \frac{60}{4} = 15