How will the area of the lateral surface of the cylinder change if its height is increased by 4 times

How will the area of the lateral surface of the cylinder change if its height is increased by 4 times and the diameter is reduced by 2 times?

Let’s write down the formula for finding the lateral surface of the cylinder:
S = 2 * π * R * h = π * d * h = πdh.
Now let’s make all the changes in the parameters, according to the condition of the problem and write down what is the area of the lateral surface after the changes:
S2 = π * d / 2 * 4h = 2πdh.
Let’s compare the areas and get:
S2 / S = 2πdh / πdh = 2.
Answer: the area will double.