Lesson 5.2: Segments, Lines, Rays and their Relationship

Symbols

$\text{multipurpose indicator}$
⠐

$\text{directly over symbol}$
⠣

$\text{segment}$
⠱

$\text{line}$
⠪⠒⠒⠕

$\text{ray}$
⠫⠕

$\text{termination indicator}$
⠻

$\text{∥ parallel}$
⠫⠇

$\text{⊥ perpendicular}$
⠫⠏

Explanation

In braille some shapes may need to be modified to represent symbols in print. This is true for shapes that are positioned above other symbols in order to represent the symbols for a segment, line, or ray. Typically these shapes are defined by two distinct points on the segment, line, or ray. In print, the symbol for a segment, line, or ray is then placed directly above the two letters used to name the shape. A segment symbol is a horizontal bar above the letters. A line is a horizontal bar with arrows on either side of the bar pointing to the left and to the right indicating that the line goes on forever in both directions. Finally, a ray has a horizontal bar with an arrow typically only on the right side indicating that the ray starts at one point and continues onward forever in the direction of the other letter used to name the ray.

Representing these shapes is a five step process.

Two symbols that are typically used with the symbols for segment, line, and ray are the parallel and perpendicular symbols. In print, the symbol for parallel is two vertical lines beside each other indicating two lines that never cross. In braille the symbol for parallel is a two-cell symbol made up of the shape indicator followed by dots one two three. The symbol for perpendicular in print is a vertical line with an intersecting horizontal line at the bottom to indicate two lines that intersect at a right angle. In braille, the symbol for perpendicular is a two-cell symbol made up of the shape indicator followed by one two three four.

In the following examples and exercises, the symbols for segment, ray, and line are superscribed over the letters that make up the segment, ray or line. These geometric shapes are typically named using two letters, although you may see them with more. The braille configurations for the segment, ray, and line are described below.

A segment is represented by a horizontal bar, dots one five six.

A ray is represented by the shape indicator followed by the barb of an arrow. This would be dots one two four six followed by dots one three five. The line is represented by the shape indicator followed by an arrow with barbs on both ends. This would be dots one two four six, dots two four six, dots two five, dots two five, and dots one three five.

Example 1

$\overline{\mathrm{AB}}$

Example 2

$\overrightarrow{\mathrm{AB}}$

Example 3

$\overleftrightarrow{\mathrm{AB}}$

Example 4

$\text{Do}\overleftrightarrow{\mathrm{AB}}\text{and}\overleftrightarrow{\mathrm{BA}}\text{name the same line?}$
⠠⠙⠕⠀⠸⠩⠀⠐⠠⠁⠠⠃⠣⠫⠪⠒⠒⠕⠻⠀⠠⠄⠁⠝⠙⠀⠐⠠⠃⠠⠁⠣⠫⠪⠒⠒⠕⠻⠀⠸⠱⠀⠝⠁⠍⠑⠀⠞⠓⠑⠀⠎⠁⠍⠑⠀⠇⠊⠝⠑⠦

Example 5

$\text{Does}\overline{\mathrm{CD}}\text{intersect}\overline{\mathrm{GH}}\text{?}$
⠠⠙⠕⠑⠎⠀⠸⠩⠀⠐⠠⠉⠠⠙⠣⠱⠻⠀⠠⠄⠊⠝⠞⠑⠗⠎⠑⠉⠞⠀⠐⠠⠛⠠⠓⠣⠱⠻⠀⠸⠱⠦

Example 6

$\parallel$
⠫⠇

Example 7

$\perp$
⠫⠏

Example 8

$\overline{\mathrm{MN}}\parallel \overline{\mathrm{XY}}$
⠐⠠⠍⠠⠝⠣⠱⠻⠀⠫⠇⠀⠐⠠⠭⠠⠽⠣⠱⠻

Example 9

$\overrightarrow{\mathrm{PQ}}\perp \overrightarrow{\mathrm{PT}}$
⠐⠠⠏⠠⠟⠣⠫⠕⠻⠀⠫⠏⠀⠐⠠⠏⠠⠞⠣⠫⠕⠻

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