Press Alt-Enter while in the formula editing window at the top of the page to add an addtional line within a cell.
The borders tool
If you are referring to Excel spreadsheets, that is called wrap text.
Since Microsoft Excel 2007, the amount of lines has been 1,048,576.
establishing and managing multiple cross-functional relationships and communication lines with other business units
It's important to use multiple lines in a line graph so that you can identify each categories without confusion.
Excel does not use leader lines, because it does not use tabs. You would find leader lines in MS Word.
the lines between cells
The horizantal lines
The actual lines are known as gridlines, both vertical and horizontal. A vertical line of cells is known as a row.
The graph of a continuous function will not have any 'breaks' or 'gaps' in it. You can draw it without lifting your pencil or pen. The graph of a discrete function will just be a set of lines.
parallel lines are diagonal lines or increasing lines
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