The geyser is cylindrical. Write the formula for the total surface area of a cylinder.

Here are the solutions to questions 1.3.1 to 1.3.3.

1.3.1

a) Cut out circles of the aerolite to be placed on both ends of the geyser.
P

b) Apply glue to the circular pieces of the aerolite.
Q

c) The strips of aerolite are wrapped around the pipes.
There is no matching picture (P-U) for this statement, as the pictures show wrapping the geyser, not pipes.

d) Roll the aerolite around the lateral surface of the geyser.
T

e) Use duct tape to secure the aerolite around the lateral surface.
U

f) Attach the circular pieces of the aerolite to the geyser.
R

1.3.2

The geyser is cylindrical. The total surface area of a cylinder is given by the sum of the area of the two circular bases and the lateral surface area.
Area of two circular bases $= 2 \times \pi \times \text{radius}^2$
Lateral surface area $= 2 \times \pi \times \text{radius} \times \text{height}$
Total surface area $= 2 \times \pi \times \text{radius} \times \text{height} + 2 \times \pi \times \text{radius}^2$

Comparing this with the given options:
A: $\pi \times \text{radius}^2 \times \text{height} + 2 \times \pi \times \text{radius}$
B: $\pi \times \text{radius} \times \text{height} + \text{length} \times \text{width}$
C: $2 \times \pi \times \text{radius} \times \text{height} + 2 \times \pi \times \text{radius}^2$
D: $\frac{1}{2} \times \text{base} \times \text{height}$

The correct formula is option C.

The letter next to the question number (1.3.2) is C.

1.3.3