Answer:
[tex]\large\boxed{a.\ 7200\pi\ mm^2}[/tex]
Step-by-step explanation:
The formula of a surface area of a cylinder:
[tex]S.A.=2\pi r(r+H)[/tex]
r - radius
H - height
We have r = 40mm and H = 50mm. Substitute:
[tex]S.A.=2\pi(40)(40+50)=80\pi(90)=7200\pi\ mm^2[/tex]
