Karla uses a traditional, manual method of constructing perpendicular lines, using a straightedge while Daryl uses a latest drawing tools to draw them.
Both the methods are correct, however the amount of effort and time taken will vary for these two different methods.
Since Karla is constructing perpendiculars manually so she has to go through all the methods carefully, from placing the straightedge to marking the arcs and joining them correctly. It will take her a little longer and more effort to get the accurate results.
On the contrary, the drawing tool used by Daryl will be much more efficient as he can construct perpendicular lines just by specifying a point in no time.
