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Tangents – trigonometry – math

By |2018-04-11T09:30:18+00:00July 29th, 2017|Math|

Tangents: This line is tangent to a circle. What is a tangent? A tangent, like a sine or a cosine, is a mathematical way of thinking about a kind of movement that happens in nature. A tangent is really just a rephrasing of the same information we already had for calculating the sine function. Lines and circles [...]

What is skew? Skew lines – Geometry

By |2017-07-29T13:03:09+00:00July 29th, 2017|Math|

These two green lines are skew to each other. Skew is a pretty cool word, and it sounds like it means something really weird, and it kind of does. It means lines that go any which way. It describes any two lines that aren't either parallel or perpendicular to each other, and that don't cross each other anywhere (so [...]

Rectangle – area and perimeter

By |2018-04-23T16:01:22+00:00July 29th, 2017|Math|

This is a rectangle. A rectangle is a flat shape, in one plane. It's defined by four points at the four corners. A rectangle has two sides of equal length opposite each other, and two other sides of equal length opposite each other, and four corners, all right angles (90 degree angles). A square is a special kind of rectangle. [...]

Perpendicular lines – Simple geometry

By |2017-07-29T11:41:47+00:00July 29th, 2017|Math|

Perpendicular lines Two lines are perpendicular if they cross at right angles. You can test this by extending the lines until they cross (if they do not cross then they are parallel). Where the two lines cross, draw a right triangle, and then see whether the triangle conforms to the Pythagorean Theorem - if so, then your lines are crossing [...]

Parallel lines – Simple geometry

By |2017-07-29T11:36:46+00:00July 29th, 2017|Math|

Two parallel lines Two lines are parallel if they are in the same plane but they can go on forever without ever crossing. You can test this by seeing if you can draw a third line that crosses both lines at right angles (it is perpendicular to them). Parallel lines can be close together or far apart, [...]

Diameter of a circle – Geometry

By |2017-07-29T09:34:48+00:00July 29th, 2017|Math|

The geometry of a circle The diameter of a circle is the distance across the circle at the widest part of the circle. The diameter is always equal to twice the radius of the circle, because the radius starts from the center of the circle and goes straight to the edge. Learn by doing: measure the diameter [...]