lens
The answer will depend on what the tube is made from and how thick its walls are.
It is a shape that is like a toothpaste tube which has a circular lid which is the same size as the tube below it.
This is a triangular prism, so the volume is base times height. Area of the triangular base is half the base times the height. 8 * 5.2 / 2 = 20.8 in² Take this a multiply by 12 and get 249.6 in3 ■
Cylinder can be used to describe any circular cross-section tube. Any particular ones in mind?
Triangular prism
Tube pitch is the center-to-center distance between parallel straight tubes in a uniform bundle. The tube layout pattern is usually triangular or square. The tube pitch is usually about 1.25 times the outer diameter of the tubes.
I assume you mean a 4 x 2 square tube that is loaded in the direction of the 4 inch dimension; then it is stronger than a 4 inch channel with flange width of 2 inches loaded in the direction of the 4 inch dimension, because the square tube has more inertia
pyloric sphincter
No, eye balls are circular.
lens
It is called the because of it's shape. If you look at the Paris Underground it is square but the London Underground has tube shaped tunnels and stations. Even the trains are tube shaped, apart from the lines which go overground for quite a way like the District and Circle line.
Sloane Square tube station was created in 1868.
Russell Square tube station was created in 1906.
Generally, square- or circular-section copper. Some distribution transformers use insulated sheets of aluminium, rolled to form a layered tube.
auditory (pharyngotympanic) tube
A tube is a type of cylinder, which has two circular faces, one at each end. It also has three edges - two circular edges around the faces and one curved edge around the side. A tube has no vertices, as vertices are defined as the points where edges meet, and a tube's edges do not meet at any points.