According to the given information, a height of 2.4 cm of a solid cylinder with a diameter of 1.4 cm, where the same conical cavity is hollowed out at the same height and diameter
So the dimensions we know are
Height of full cylinder (v) = 2.4 cm
Diameter of solid cylinder (d) = 1.4 cm
Therefore, the radius of the solid cylinder (r) = 0.7 cm
As we know, the formula of the total surface of the remaining solid is equal to the curved surface of the cylinder + the area of the base of the cylinder + the curved surface of the cone
Now we know that the curved surface of the cylinder =
Area of the base of the cylinder and Curved surface area of the cone .
Where slant height which is given as
Therefore, Total surface area of the remaining solid =
Now substituting the values in the above formula, we get
So, Total surface area of the remaining solid is equal to .