Final answer:
The two small triangles and a square on the ruler in word processing programs used to set text indents are known as indentation markers.
Step-by-step explanation:
The position of each indent level on the ruler in word processing programs is represented by two small triangles and a square known as indentation markers.
In the context of a ruler used in word processing, these markers allow the user to set how far text is indented from the left or right margins. The top triangle is typically used to change the first line indent, the bottom triangle adjusts the hanging indent, and the square moves both the first line and hanging indents simultaneously. It's important to understand how these markers work, as they help in formatting documents to look professional and aid in creating the structure necessary for good readability.