Comparing and Contrasting Euclidean, Spherical, and Hyperbolic Geometries

1764 Words 8 Pages
When it comes to Euclidean Geometry, Spherical Geometry and Hyperbolic Geometry there are many similarities and differences among them. For example, what may be true for Euclidean Geometry may not be true for Spherical or Hyperbolic Geometry. Many instances exist where something is true for one or two geometries but not the other geometry. However, sometimes a property is true for all three geometries. These points bring us to the purpose of this paper. This paper is an opportunity for me to demonstrate my growing understanding about Euclidean Geometry, Spherical Geometry, and Hyperbolic Geometry.
     The first issue that I will focus on is the definition of a straight line on all of these surfaces. For a
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These symmetries include: reflection-in-the-line symmetry, reflection-perpendicular-to-the-line symmetry, half-turn symmetry, rigid-motion-along-itself symmetry, central-symmetry, and self-symmetry. If a line on a hyperbolic plane satisfies these conditions then we can say that it is straight. I have included my homework of my definition of a straight line on a hyperbolic plane so that one can see why these conditions must be satisfied.
     The next issue that I will address for these three geometries is the definition of an angle on all three surfaces. The definition that I will give applies to all three surfaces. There are at least three different perspectives from which we can define “angle”. These include: a dynamic notion of angle-angle as movement, angles as measure, and angles as a geometric shape. A dynamic notion of angle involves an action which may include a rotation, a turning point, or a change in direction between two lines. Angles as measure may be thought of as the length of a circular arc or the ratio between areas of circular sectors. When thinking of an angle as a geometric shape an angle may be seen as the delineation of space by two intersecting lines. I have provided my homework assignment on my definition of an angle so that one can see the reasoning of my definition for all three surfaces. However, my homework assignment does not ask to define an angle on a hyperbolic plane. This is because a region on a hyperbolic plane