[Maths-Education] Ratio and Proportion
Anne Watson
anne.watson@educational-studies.oxford.ac.uk
Thu, 04 Oct 2001 13:52:43 +0100
Dave raises a point which has also puzzled me. The nonsense is revealed
if you consider two similar triangles drawn next to each other. Comparing
the sides doesn't fit with the "part to part" nor the "part to whole"
definitions, so this comparison is neither ratio nor proportion. So tuck
the smaller triangle inside the larger so that they have a common
vertex. Then two pairs of sides can be compared part to part, but the
third side still doesn't fit the Strategy guidelines! Try again. This
time, think about comparing the three sides of each triangle to each other
as a three-part-ratio (part to part to part???) , then the three-part
ratios of both triangles are equal, but this is light-years away from what
is presented in the Strategy.
Help!