How do you calculate the surface area of a cylinder? - Answers

OK. Let me give you an example.Lets suppose the radius of a cylinder is 3.5 ft, the Diameter is 7 ft and the height is 14 ft. find the surface area. Show all your work.In order to find the surface area you have to calculate all the areas. and then add them up.Area of a circle is Pi times the radius squared.Pi is 3.14Area of a circle is 3.14 X 3.5 ft2Area of a circle is 3.14 X 12.25 ftArea of a circle is 38.465 ft2Now a cylinder has two circles that equal each other, so all we have to do is multiply 38.465 ft2 X 2.Area of both circles is 76.93 ft2Second you have to find the area of the rectangle that is wrapped around the cylinder. When the rectangle is wrapped around the cylinder it creates a circumference which is the length of the rectangle.So we need to find the circumference.Circumference is Pi times the diameter.Pi is 3.14Circumference is 3.14 X DCircumference is 3.14 X 7 ftCircumference is 21.98Now that we know the Circumference we can find the area of the rectangle wrapped around the cylinder.Area of a rectangle is Length times the Width.(The height of a cylinder is also the width of the rectangle).Area of a rectangle is 21.97 X 14 ftArea of a rectangle is 307.72 ftOK. we calculated all the areas. BUT we still aren't done. We have to add all the areas up.76.93 ft2 + 307.72Surface Area is 384.65