All points, straight objects, circles, arcs, interiors, point loci, measurements, parameters, calculations, functions, function plots, angle markers, and action buttons have labels. A label is text used to identify the object.
•Show or hide labels using the Text tool or Display  Show/Hide Labels.
•Reposition labels by dragging with the Text tool.
•Edit labels by doubleclicking with the Text tool, by choosing Display  Label Objects, or by choosing Edit  Properties  Label.
When you edit a label, you can insert subscripts, symbols, Greek letters, and Unicode using support built into Sketchpad or using Unicode input methods available from your operating system.
•Change how labels are used in custom tools by choosing Edit  Properties  Label.
Italics: Sketchpad normally uses italics for most objects, including geometric objects, measurements, parameters, and userdefined function names. Calculations and function definitions appear using mathematical italics in a way that is consistent with the most common standards for mathematical typesetting.
To turn mathematical italicization on or off, choose Edit  Preferences  Text and use the Italicize all mathematical labels checkbox.
Default Labels: Here are the default labels Sketchpad uses for various kinds of objects:
Object 
Default Label 
A, B, C, … 

j, k, l, … 

c1, c2, c3, … 

C1, C2, C3, … 

a1, a2, a3, … 

A1, A2, A3, … 

P1, P2, P3, … 

L1, L2, L3, … 

Cannot show a label 

f, g, h, … 

y=f(x), … 

m1, m2, m3, … 

t1, t2, t3, … 

Cannot show a label 

Cannot show a label 

Label depends on action 
* When possible, a polygon with six or fewer vertices is labeled according to its vertices.
If Sketchpad runs out of letters with which to label points or straight objects, it starts over with A1 and j1.