Article in English: What if, rather than finding the distance that a moving object has traveled, you need to find the distance between two stationary objects? In cases like this, the speed-based distance formula described above won't be of any use. Luckily, a separate distance formula can be used to easily find the straight-line distance between two points. However, to use this formula, you'll need to know the coordinates of your two points. If you're dealing with one-dimensional distance (such as on a number line), your coordinates will be two numbers, x1 and x2. If you're dealing with distance in two dimensions, you'll need values for two (x,y) points,  (x1,y1) and (x2,y2). Finally, for three dimensions, you'll need values for (x1,y1,z1) and (x2,y2,z2). Calculating one-dimensional distance between two points when you know the value for each is a cinch. Simply use the formula d = |x2 - x1|. In this formula, you subtract x1 from x2, then take the absolute value of your answer to find the distance between x1 and x2. Typically, you'll want to use the one-dimensional distance formula when your two points lie on a number line or axis.  Note that this formula uses absolute values (the "| |" symbols). Absolute values simply mean that the terms contained within the symbols become positive if they are negative. For example, let's say that we're stopped by the side of the road on a perfectly straight stretch of highway. If there is a small town 5 miles ahead of us and a town 1 mile behind us, how far apart are the two towns? If we set town 1 as x1 = 5 and town 2 as x1 = -1, we can find d, the distance between the two towns, as follows:  d = |x2 - x1| = |-1 - 5| = |-6| = 6 miles. Finding distance between two points in two-dimensional space is more complicated than in one dimension, but is not difficult. Simply use the formula d = √((x2 - x1)2 + (y2 - y1)2). In this formula, you subtract the two x coordinates, square the result, subtract the y coordinates, square the result, then add the two intermediate results together and take the...

Summary in Vietnamese:
Tìm tọa độ không gian của hai điểm. Tìm khoảng cách trên đường thẳng một chiều bằng cách trừ tọa độ của hai điểm. Tìm khoảng cách trên mặt phẳng hai chiều bằng định lý Pytago. Tìm khoảng cách trong không gian 3 chiều bằng cách phát triển công thức dùng cho mặt phẳng 2 chiều.