Answer:
The area of the circular ends of the cylinder.
Explanation:
The total surface area of a right circular cylinder is
... total area = area of circular ends + lateral surface area
The lateral surface area can be considered to be a rectangle whose length is the circumference of the cylinder and whose width is the height of the cylinder. For a cylinder of radius r and height h, this is described by the product ...
... lateral surface area = 2πrh
The area of the (congruent) circular ends is twice the area of one of the ends. That area is the area of a circle of radius r, so is described by ...
... area of one circular end = πr²
Then ...
... area of circular ends = 2πr²
and the total area of the cylinder is ...
... total area = 2πr² + 2πrh . . . . matches the formula in your problem statement