How to Calculate the Distance Between Parallelogram Points

If you are struggling through a geometry exercise that asks you to provide the missing measurements on a series of parallelograms, you can find the distance between two points on a parallelogram by using one basic formula: The Distance Formula.

Things You'll Need

• The Distance Formula: √(x2 -- x1)^2 + (y2 -- y1)^2

Instructions

1. Draw a big plus sign on a piece of paper (graph paper works the best, as the lines are already drawn for you) and place small vertical marks along the horizontal line (the x-axis), numbering each mark with negative numbers to the left of zero (where the lines intersect) and positive numbers to the right of zero. Repeat for the vertical line---positive numbers go up and negative numbers go down.

2. Mark the parallelogram points with a dot at the intersecting points. Let's say point A is (3, -4), point B is (3, 3) and point C is (-3, -4). Connect the dots.

3. Find the distance between B and C, first labeling B as (x2, y2) and point C as (x1, y1), as these are the points for which we need to find the distance. This is where we need The Distance Formula.

4. Plug the numbers into the distance formula:

   √[3 -- (-3)]^2 + [3 -- (-4)]^2
   √[6]^2 + [7]^2

   √36 + 49
   √85 = ≈ 9.4

Tips & Warnings

• Always complete steps inside parentheses before squaring. Graph paper will be better to use than blank paper, especially if you're new to this formula. Graph paper is already marked specifically for work like this.

• If you square the numbers before you complete the equation in parentheses, you could come up with the wrong solution.

References

• Essentials of College Algebra; Richard N. Aufmann and Richard D. Nation; 2006