Question

what is the formula for finding the area of hollow cylinder

Answer 1

Area of a cilynder is[math] 2*pi*r(h+r)[/math]Explanation :Cylinder has 3 surfaces.Two circular surfacesand a curved surface.Area of a circular surface[math] = pi*r^2[/math]Let the height of the cylinder ish. This means the height of the curved surface is alsoh.Area of the curved surface[math] = 2*pi*r*h[/math]Area of the cylinder isthe sum of the areas of three surfaces.Therefore the area of the cylinder[math] [/math][math]= pi*r^2 + pi*r^2 + 2*pi*r*h[/math][math]=[/math][math]2*pi*r^2 + 2*pi*r*h[/math]Taking common[math] 2*pi*r[/math][math]=[/math][math]2*pi*r(r+h)[/math]… Proved.
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