A technician often has to sketch or design ductwork and the other parts of an HVAC system. Sometimes you have to sketch the room or building you are working with. This means working with lines, angles ...

In our mind’s eye, the universe seems to go on forever. But using geometry we can explore a variety of three-dimensional shapes that offer alternatives to “ordinary” infinite space. When you gaze out ...

The sum of interior angles in a quadrilateral is 360°. This fact is a more specific example of the equation for calculating the sum of the interior angles of a polygon: \(\text {Sum of interior angles ...

A nonagon has nine sides and a decagon has ten sides. To understand polygons, a good understanding of other angle rules, including triangles and quadrilaterals can be helpful. The word for the name of ...

One hypothesis about the shape of the universe is that the universe is in the space of Euclidean geometry and flat. In Euclidean geometry, it is assumed that straight lines extend everywhere, planes ...