Find the surface area of tube of diameter 3.5cm and 30cm long?

To find the surface area of a tube, we need to find the lateral surface area and the surface area of the two circular ends.

Given:
Diameter = 3.5 cm
Radius = 3.5/2 = 1.75 cm
Length = 30 cm

Lateral Surface Area = 2 * π * r * h
= 2 * π * 1.75 * 30
= 105π cm²

Surface Area of two circular ends = 2 * π * r²
= 2 * π * 1.75²
= 2 * π * 3.0625
= 6.125π cm²

Total Surface Area = Lateral Surface Area + Surface Area of two circular ends
= 105π + 6.125π
= 111.125π cm²

Therefore, the surface area of the tube is 111.125π cm² or approximately 349.5 cm².

The surface area of a tube is given by the formula:

$$A = 2\pi rh + 2\pi r^2$$

Where:

- A is the surface area
- r is the radius of the tube
- h is the height of the tube

In this case, the diameter of the tube is 3.5 cm, so the radius is 1.75 cm. The height of the tube is 30 cm.

Substituting these values into the formula, we get:

$$A = 2\pi (1.75 cm)(30 cm) + 2\pi (1.75 cm)^2$$

$$A = 345.58 cm^2 + 19.24 cm^2$$

$$A = 364.82 cm^2$$

Therefore, the surface area of the tube is 364.82cm².