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UNIT 7 (Polyhedra and Platonic Solids ((Solids have properties (special…
UNIT 7
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Gradation refers to gradual variation of the unit form, and it can be used in three
different ways:
- Gradation of size but repetition of shape.
- Gradation of shape but repetition of size.
- Gradation of both shape and size.
If one plane follows another in a straight manner, then the two vertical edges of the planes trace two parallel straight lines.
DIRECTIONAL VARIATION: Can be arranged in radiation direction
Can form a shape with curves left and right.
Rotation on a horizontal axis
Rotation on its own plane
Means that the corners or edges of each plane are moved from one position to another.
The planes can be curled or bent
Three-Dimensional forms
We define a three-dimensional form as any form that has three dimensions. What are these three dimensions? They are width, height and depth.
You see that it takes up space front and back, sideways, and up and down.
three-dimensional geometry is just an extension of two-dimensional geometry; many of the same principles apply.
Non Polyhedra
Non-polyhedra describes any geometric solid that has any surface that is not flat, like a sphere, cone, or cylinder
Cylinder: It has a flat base and aflat top. The base is the same as the top. From base to top the shape stays the same , It has one curved side
Cone :It has one curved side. The pointy end of a cone is called the apex, The flat part is the base
Sphere: It is perfectly symmetrical, All points on the surface are the same distance "r" from the center. It has no edges or vertices (corners) ,It has one Surface
Torus • it can be made by revolving a small circle (radius r) along a line made by a bigger circle (radius R). • It has no edges or vertices