The midpoint
They must be collinear.
Do you mean "Between two other points? If yes, when it lies on a straight line between both points that are farther away and on the same line.
Twice the distance between a point and halfway to the other point.
since you know of one points and the halfway point between the other point. just multiply the halfway point by 2 and this is the total distance between the two points.
The halfway point between two other defined points.
Length or distance between two points.
wavelength. It is the distance between two consecutive points that are in phase in a wave, such as between two high points or two low points. Wavelength is typically measured in meters or any other unit of length.
Then one point is 20 units away from the other.
a line segment is not a point but a series of points between two definite end points
grravity or some other force moves it
with no other details I can only explain it as the distance between point R and point A. More details are needed if you want that distance when compared with other points.