Warm Up

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Preview
Warm Up
California Standards
Lesson Presentation
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Warm Up Solve. Use 3.14 as an estimate for
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1. The diameter of a circle is 12 in. What is
the circumference?
?37.68 in.
2. The radius of a circle is 9 cm. What is its
circumference?
? 56.52 cm
3. Find the area of a circle with a 12 ft radius.
? 452.16 ft2
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Vocabulary
3D - polyhedron face edge vertex cube base
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A polyhedron is a three-dimensional object with
flat surfaces, called faces, that are polygons.
When two faces of a three-dimensional figure
share a side, they form an edge. A point at which
three or more edges meet is a vertex (plural
vertices).
A cube is formed by 6 congruent square faces. It
has 8 vertices and 12 edges.
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Teacher Example 1 Identifying Faces, Edges, and
Vertices Identify the number of faces, edges, and
vertices on each three-dimensional
figure. A. B.
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Student Practice 1 Identify the number of faces,
edges, and vertices on each three-dimensional
figure. A. B.
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Two types of polyhedrons are prisms and pyramids.
Prisms and pyramids are named for the shape of
their bases. A base of a three-dimensional figure
is a face by which the figure is measured or
classified.
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Other three-dimensional figures include cylinders
and cones. These figures are not polyhedrons
because their surfaces are not polygons.
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Teacher Example 2A Naming Three-Dimensional
Figures Name the three-dimensional figure
represented by the object.
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Teacher Example 2B Naming Three-Dimensional
Figures Name the three-dimensional figure
represented by the object.
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Teacher Example 2C Naming Three-Dimensional
Figures Name the three-dimensional figure
represented by the object.
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Student Practice 2A Name the three-dimensional
figure represented by the object.
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Student Practice 2B Name the three-dimensional
figure represented by the object.
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Student Practice 2C Name the three-dimensional
figure represented by the object.
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Lesson Quiz
1. Identify the number of faces, edges, and
vertices in the figure shown. Identify the
figure described 2. two parallel congruent
circular faces connected by a curved surface 3.
one flat circular face and a curved lateral
surface that comes to a point
8 faces, 18 edges, and 12 vertices
cylinder
cone