yesYes.
No, it is true that the Panama Canal is approximately located on a longitude of 80 degrees W.
False.
Yes, all points east and west of the Prime Meridian are both between 0 and 180 degrees longitude because there are a total of 360 degrees of longitude on a globe divided into 180 degrees on each of the eastern and western hemispheres.
Lines of longitude meet at the poles, both North and South. At the North Pole, all lines of longitude converge and meet at a single point. The same holds true for the South Pole, where lines of longitude also converge and meet at a single point.
yesYes.
No, it is true that the Panama Canal is approximately located on a longitude of 80 degrees W.
False.
Yes, all points east and west of the Prime Meridian are both between 0 and 180 degrees longitude because there are a total of 360 degrees of longitude on a globe divided into 180 degrees on each of the eastern and western hemispheres.
Every meridian of constant longitude is nominally a semi-circle, equal in length to all other meridians, and joining the Earth's north and south poles.
Lines of longitude meet at the poles, both North and South. At the North Pole, all lines of longitude converge and meet at a single point. The same holds true for the South Pole, where lines of longitude also converge and meet at a single point.
That's true of the Mercator projection, among others.
The meridians meet at the poles, which are the points on Earth's surface where the lines of longitude converge. At the North Pole, all lines of longitude meet, and the same is true for the South Pole.
To sail along a meridian, one must sail true north or true south. Meridians of longitude run N/S.
You might say that. The thing that makes it the "main" one is the fact that by international agreement, it's the meridian that's accepted as zero longitude. So whenever the longitude of a place is stated, you always know that the number means an angle measured from the "Greenwich Meridian".
There's really no such thing as flying "on longitude". Do you mean that they stay on the same line of longitude when they're flying ? That would only be true as long as an airplane is flying exactly due north or due south. Any other time, it's flying through plenty of different longitudes.
Every point in Canada has north latitude and west longitude. The same is true of the USA, except for part of Alaska's Aleutian chain, which crosses into the eastern hemisphere.