10-0
Vocab Intro
Grab a bag of playdough. Do not open
it yet. 
Warm-up
person #2
Sketch the net of the solid & include measurements.
• A polyhedron is a 3-D figure whose surfaces are
polygons. link
• All of the polygons on 3D figures are called faces.
• The line segments where faces intersect are called
edges.
• A vertex is a point where three or more edges
intersect.
Prism: a solid with the following 3 characteristics:
1. Two faces, called bases, are formed by congruent
polygons that lie in parallel planes. A prism is named
by the shape of its base.
2. The faces that are not bases, called lateral faces,
are formed by parallelograms.
3. The intersections of two adjacent lateral faces are
called lateral edges and are parallel segments.
Altitude: the segment to both bases with endpoints
in each base.
Height (h): the length of the altitude (distance
between the bases)
With your play-dough:
• Construct a triangular prism.
– Place toothpicks along the lateral edges and
altitude.
Cross Section:
the intersection of a solid and a plane
(a 2-D shape)
• Use fishing line or thread to “slice” your solid…
…parallel to the bases.
What is the shape of the cross section?
…perpendicular to the bases.
What is the shape of the cross section?
• Construct a rectangular prism.
– Place toothpicks along the lateral edges and
altitude.
Slice the prism parallel to the bases.
What is the shape of the cross section?
Slice the prism perpendicular to the bases.
What is the shape of the cross section?
How can you slice the prism to get a triangular cross
section?
A trapezoidal cross section?
Grab a bag of play-dough.
Get out your orange Surface
Area & Volume sheet
See if you can create a
triangular cross section from a
rectangular prism.
Cylinder: a solid with bases formed by congruent
circles in parallel planes.
• Construct a cylinder.
* Place toothpicks along the lateral edges.
• A cylinder is not a polyhedron!
* Place a toothpick along the altitude.
Slice the cylinder parallel to the bases.
What is the shape of the cross section?
Slice the cylinder perpendicular to the bases.
What is the shape of the cross section?
Pyramid: a solid with the following 4 characteristics:
1. All faces except one intersect at the vertex.
2. The base is the face that does not intersect at the
vertex. The base is always a polygon.
3. The faces that intersect at the vertex are called
lateral faces and form triangles. The edges that
meet at the vertex are called lateral edges.
4. The altitude is the segment from the vertex
perpendicular to the base.
* The height of each lateral face in a regular pyramid
is called the slant height, l.
• Construct a pyramid.
* Place toothpicks along the lateral edges.
* Place a toothpick along the altitude.
* Etch a slant height.
Slice the pyramid parallel to the base.
What is the shape of the cross section?
Slice the pyramid perpendicular to the base.
What is the shape of the cross section?
Cone: a circular base with a vertex.
Construct a cone.
* Place a toothpick along the altitude.
* Etch a slant height.
Slice the cone parallel to the base and
perpendicular to the base.
What are the shapes of the cross sections?