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Handout
Purple Math

Purplemath: Conventions

For Students 9th - 10th Standards
A "convention" is "just the way a thing is done!". This reference material lists some common conventions (notational assumptions) for geometry and trigonometry.
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Activity
University of Georgia

University of Georgia: Segment and Arc Length

For Students 9th - 10th
This site gives a short explanation about the segment and arc length