What’s the equator? Geography and the Earth
This globe shows the equator running around the widest part of the Earth. Where is the equator? The equator is an imaginary line running around the widest part of the Earth, [...]
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08, 2017
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07, 2017
Area of a sphere – Volume of a sphere
This is a sphere. A sphere is a three-dimensional circle. Or you could say that a sphere is the set of all the points that are at the same distance from the center [...]
29
07, 2017
Solids – Platonic solids – Geometry
Pyramid Just as a plane is made of an infinite number of lines, a solid is made of an infinite number of planes. These planes are right next to each other, like [...]
29
07, 2017
Checking the surface area of a sphere
Did you ever have to wrap a basketball as a present? To see how the surface area of a sphere is really 4πr2, find a ball to wrap (a basketball works well). Cut some [...]
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07, 2017
Definition of a circle – Geometry
A circle is the set of points on a plane that are all the same distance away from a center point. A circle is the set of points on a plane that are all [...]
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07, 2017
Who was Archimedes? Eureka!
Archimedes was from Syracuse, Sicily. Here you see it with Mount Etna in the background When did Archimedes live? Archimedes was born about 287 BC, so he was a little younger [...]
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06, 2017
Math and Numbers in Ancient China
Chinese numbers: number rods Chinese numbers People in China were using written numbers by about 1500 BC, in the Shang Dynasty. This is about two thousand years later than people began [...]
