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How Letters Appear
Letters appear in geometry to name or locate points and to give the
lengths of sides and hieghts in formulas for areas of rectangles and
triangles. As a student, you will accept the use of a letter as a
length of a side or line segment. The letter than has meaning.
Formulas for perimeters, areas and volumes provide introduce the
algebraic role of letters as placeholders for physical or geometric
amounts and quantities.
The site area on solving linear
equation with and without stick diagrams uses letters to denote
the length of a line segment. But the length is unknown. The stick
diagram shows how to find the unknown length by adding, subtracting,
duplicating and dividing stick diagrams. The stick diagram three column
format also introduces the algebraic view of solving linear equations
along the diagrams.
The stick diagrams are used here to introduce and build your algebraic
writing and reasoning skills and sense. And after seeing and do several
examples with the stick diagram method, you should be able to solve
linear equations without stick diagrams. Then the algebraic idea of
letting a letter stand for an unknown numbers instead of an unknown
length will have been understood, we hope. Good luck.
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