206 GEOMETRY • DIAGONAL LINES
Parallel lines
A straight line that slants is called a diagonal line.
A diagonal line is not vertical or horizontal. Another
name for a diagonal line is an oblique line.
Diagonals inside shapes
In geometry, the word diagonal has
another, more exact meaning.
Angles on a straight line
shape. It joins two corners that are
not next to each other.
Straight lines can be
horizontal, vertical,
or diagonal.
Here are some examples of a
diagonal inside a shape. We have
shown one diagonal on each shape.
The more sides a shape has, the
more diagonals it will have.
Look at this picture of a zip
wire. It is made of horizontal,
vertical, and diagonal lines.
Diagonal
Diagonal
Diagonal
206_207_Diagonal_lines.indd 206 29/02/2016 18:04