Jawabanmu

2014-06-10T21:18:56+07:00
Luas = 1/2 x d1 x d2 
    48 = 1/2 x 8 x ( x+1)
    48 = 4 x ( x+1 )
    48 = 4x + 4
    44 = 4x 
x = 11 cm

semoga membantu ... :)