Question

In the surface area formula for cylinders, which expression represents lateral area

Answer 1

The total surface are of cylinder comprises of the lateral or curved surface area + the area of the flat surface on the top and bottom

The lateral surface area is calculated this way

curved area of the face × height

Here it is a circle and hence its circumference is 2πr

Hence the formula become

2πr × h = 2πrh

So 2πrh is the part that represents the curved area of the cylinder

(Additional info: The area of the faces is given by πr² for one side, since a cylinder has 2 faces

we have πr²+πr²=2πr²

Hence the total surface area is 2πrh +2πr²)