Final answer:
The total volume of plastic used to make the pipe is 157.1 cm³.
Step-by-step explanation:
To calculate the total volume of plastic used to make the pipe, we need to find the volume of the pipe and then subtract the volume of the hollow part. The volume of a cylinder is given by the formula V = πr²h, where r is the radius and h is the height. In this case, the height of the pipe is 50 cm and the radius is half the difference between the internal and external diameters. So, the radius is (10 cm - 8 cm) / 2 = 1 cm. Plugging these values into the formula, we get V = 3.142 x (1 cm)² x 50 cm = 157.1 cm³.
Now, we need to subtract the volume of the hollow part of the pipe. The volume of a hollow cylinder is given by the formula V = π(R² - r²)h, where R is the external radius, r is the internal radius, and h is the height. In this case, the external radius is 4 cm and the internal radius is 3 cm. Plugging these values into the formula, we get V = 3.142 x ((4 cm)² - (3 cm)²) x 50 cm = 314.2 cm³.
Finally, we subtract the volume of the hollow part from the volume of the pipe to get the total volume of plastic used: 157.1 cm³ - 314.2 cm³ = -157.1 cm³.