: How to draw the perpendiculars from the incentre in Inkscape? I have a triangle ABC. I know how to draw and find the incentre O (Extensions → Render → Draw from triangle → Incentre).

@Samaraweera207

Here's one method. There may be others of course.


Mark the origin of your incentre with guides.
Draw squares from the intersection of each triangle side and guide, to the centre origin (hint: Hold down CTRL as you click and drag to constrain to a square).
Rotate each square so that the other corner intersects with the triangle
Draw a line from the centre origin, to the external corner of each square
Delete the squares, and turn the perpendicular paths into guides using Object → Object to guides.
Draw the perpendicular lines using the guides.

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@Holmes874

The ckassical elementary construction of a normal from a given point by drawing three circles work. The orange line is the resulted normal:



It only needs trimming, See the next method for it.

If there's no need of a puristical glaze,


make copies of the triangle sides (=select, Ctrl+D). If the triangle happens to be a closed shape, it's no use to split it, but draw new lines with the pen tool. If you have the point snaps on and high zoom, they will fit perfectly.
rotate them 90 degrees (Object > Rotate 90 degrees)
move by dragging the line with the usual selection tool until the end snaps to the incentre
trim.


Trimming needs the node editing tool. Double click at the crossing to create a new node, delete the node from the exessive end. The extra part vanishes.

Be sure that all snaps to points are in use, no snap to the grid.

Here's a sparse non-live visualization of the costruction of one normal:




one side is selected, duplicated and rotated 90 degrees
dragged to the incentre
trimmed

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