Geometry in carpentry. Simple formula for determining the radius of an arc

In wooden products, parts with a smooth arc are often found. These arcs can be marked using tools at hand, such as paint cans or a flexible ruler.

But there is not always an object of a suitable diameter, and it is also not always possible to draw an even arc along a bent ruler.

The best way to accurately mark the arc is to use a pair of compasses, regular or improvised. How to quickly do it look here.

In order to use a compass, you need to know the radius of the arc. Usually, the distance between the extreme points and the height of the arc from the edge of the part are known.

You can calculate the radius of an arc by knowing only these two dimensions. And the formula for calculating the radius looks like this.

By the way, it is easily derived using the Pythagorean theorem. (And again school geometry)

And then a rail is applied to the marked center of the arc, a line is drawn on it at a right angle to the part, and a compass is already placed on this line to draw the arc.

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