Question bcfa0

The diameter of the base is $D = 25 c m$ hence the radius is $R = 12.5 c m$
The radius of the circle base is r = R – thickness = 12.5 – 1 = 11.5 cm
The height is $h = 20 c m$
The whole Surface Area of the pipe = 2 πR h + 2π r h + 2 π( R^2 - r^2 ) = 2*3.14 * 12.5 * 20 + 2 * 3.14 * 11.5 * 20 + 2 * 3.14 ( 12.5^2 - 11.5^2 ) = 1570 + 1444.44 + 6.28 ( 156.25 – 132.25 ) = 3014.4 + 148.8 = 3163.2 cm^2 #