Angle & Protractor Guides
Short, practical guides for students, parents, teachers and DIYers.
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How to Use a Protractor
Measure and draw angles step by step, and avoid the most common mistakes.
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How to Read a Protractor
Inner vs. outer scale, counting tick marks, half degrees and 360° protractors.
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Measure an Angle Without a Protractor
Seven methods: rise over run, chord, paper folding, compass, 3-4-5 rule and more.
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Types of Angles
Acute, right, obtuse, straight, reflex and full angles, plus angle pairs.
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Degrees to Radians
The formula, exact π values, a conversion chart and calculator tips.