you will need: a straightedge lesson 10.1 the geometry of solids handout

You will need:

• a straightedge

Lesson 10.1The Geometry of Solids

Handout

The Geometry of Solids

Objective To learn the vocabulary of polyhedrons--prisms,

pyramids, spheres, cylinders, and cones.

What do we call a two dimensional geometric figure?

What is a three dimensional geometric figure called?

crystals

Some real-world geometric solids occur in nature:

diamonds

graphite

Other geometric solids are man-made:

baseballs hockey pucks

Other geometric solids are man-made:

soup cansbuildings

Polyhedron - a solid formed by polygons that enclose a single region in space.

Faces - the flat polygonal surfaces of a polyhedron.

Edge - a segment where two faces intersect.

Vertex - the point of intersection of three or more edges.

What type of polygon is this???

How do we know??

** Exception: a polyhedron with four faces is called a tetrahedron.

** A polyhedron is classified by its number of faces.

Regular Polyhedron

• each face is enclosed by a regular polygon.

• each face is congruent to the other faces.

• the faces meet at each vertex in exactly the same way.

What is a prism???

Prism - a polyhedron with two faces (bases) that are congruent, parallel polygons. The other faces are called lateral faces that are parallelograms.

The lateral faces meet to form the lateral edges.

Right Prism- a prism whose lateral faces are rectangle.

* Its lateral edges are perpendicular to its bases.

A prism that is not a right prism is called an oblique prism.

* The length of the altitude is the height of the prism.

Pyramid - a solid with one base whose lateral edges meet at a common vertex.

The altitude of the pyramid is the perpendicular segment from its vertex to the plane of the base.

Sphere - is the set of all points in space at a given distance from a point.

Hemisphere - is half a sphere and its circular base.

The circle that encloses the base of a hemisphere is

called a GREAT CIRCLE.

(plane that passes through the center)

Cylinder - a solid with parallel, congruent, circular bases.

If the axis of a cylinder is perpendicular to the

bases, then the cylinder is a right cylinder.

Cone - a solid with one circular base and a vertex.