Good afternoon, dear guests and subscribers of the "Build for myself" channel!
Below are 3 techniques for restoring a perpendicular or building a right angle on the ground to any straight line. These activities are very important in construction when creating axes on a plan and when constructing raffles for further construction of foundations or walls.
Having only a piece of any rope, shoelace or cable, using these methods, you will be able to build a perpendicular absolutely accurately.
So, method number 1: Isosceles triangle
We define a point on a straight line to which we will build a perpendicular (for clarity, I stuck a skewer at this point :-)
We mark on both sides of it two equidistant points (with the help of a rope it is very easy to do this). Now we have three points that are on one straight line and two equal segments between them (in the picture below - 3 skewers).
Then, it is enough for us to determine the middle of a rope of arbitrary length (In my case, for convenience, I am on made loops at opposite ends, threw them on a peg (skewer) and pulled the rope, thereby divided it into two equal parts).
Now, we combine the ends of the rope with two extreme points and pull it over the found middle.
Perpendicular is ready (Property of an isosceles triangle, the height of which divides the base into two equal segments)
Method number 2: Intersection of two arcs
This method helps out when you only have a short rope. As in the previous method, we again need to build three points on one straight line, where the two extreme ones are equidistant from the central one.
Now, like a compass, from each extreme point we draw arcs of the same radius. The point of intersection of two arcs will give us the perpendicular to the line.
Schematically, it looks like this (point O is the point of intersection of arcs):
Method number 3: Pythagorean theorem
This is probably the most used method, which uses equal lengths in a ratio of 3: 4: 5. These segments can be measured in centimeters, meters, kilometers, or any arbitrary length that we will use.
For clarity, I made 13 knots on one rope with equal distances from each other.
Now, just stretch the rope tightly by the vertices, which are separated by 3, 4 and 5 segments. Again, I use skewers :-)))
The right angle is built!
That's all, thanks for your patience :-)))
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