luas tabung.... .....diametr 21 .. .....tinggi 40.... luas?

r=21/2=10,5
t=40

L=2πr(r+t)
L=2×22/7×10,5(10,5+40)
L=66(50,5)
L=3333 satuan luas

22/7 × 10,5^2 ×40 =
22 × 15,75 × 40 =
346.5 × 40 =
13.860