plis bantu aku ... .

gambar 1 = 4   = 2 x (1x2)
gambar 2 = 12 = 2 x (2x3)
gambar 3 = 24 = 2 x (3x4)
.
.
gambar n = 2 x (n) x (n+1)

gambar 10 = 2 x 10 x (10+1)
                  = 2 x 10 x 11
                  = 220