How to bisect a 90? angle

Solution:

Step 1 : Draw $\angle$ ABC  = 90°

Step 2 : Take any radius ( Less than half of AB )  and centre " B " draw an arc that intersect line AB at " P "  and BC at " Q " .

Step 3 : With same radius and centre " P " and " Q " draw two arcs and these arcs intersect at " R " .

Step 4 : Join BR and extend it to " D " , So BD is angle bisector of $\angle$ ABC .



Here

$\angle$ ABD = $\angle$ CBD = 45°