tolong nomer 30.......... yaaa! makasih

Luas permukaan tabung = (2 x luas alas) + luas selimut tabung
= (2 x phi x r^2) + (panjang x lebar)
= (2 x phi x r^2) + (2 x phi x r x tinggi tabung)
= (2 x 22/7 x 7^2) + (2 x 22/7 x 7 x 20)
= (44/7 x 49) + (44 x 20)
= (44 x 7) + 880
= 308 + 880
= 1.188 cm^2

r = diameter/2 = 14/2 =7 cm