Enjoying Geometry

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Welcome to the world of wacky
shapes Enjoying Geometry
By Christine S. Grigg 5th grade teacher
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Strand 3 Geometry
3.01 Identify triangles and quadrilaterals
3.03 Classify by symmetry, rotation
3.04 Sum of dimensions
Question Wheres the pattern in these
points?
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This is an ordinary garden-variety square
Add the side dimensions to find the perimeter.
This square covers 3 cells in all directions.
What is its area?
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You know because it has 4 sides the same length
and 4 right angles
If a line is 180 degrees, what is the sum of two
angles in a square? If the angles of a square
are all congruent, how many degrees are found in
a full square?
It has 4 lines of symmetry.
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The Square has 360 degrees in its angles. A
circle has 360 degrees in its interior angles.
A rhombus is a cousin. It has 4 equal sides, 2
acute angles and 2 obtuse angles.
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This is an ordinary garden-variety triangle
isosceles
2 lines equal
Equilateral three equal sides Congruent angles
equilateral
Right angle
no lines the same
scalene
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Height
Base
Triangles have 180 degree interiors and one line
of symmetry. To find the perimeter, add the
dimensions of each side. To find the area,
multiply the base times the height and divide by
2.
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This is an ordinary garden-variety rectangle
Add dimensions of the sides to find perimeter.
Multiply length by width to find area.
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Rectangle has 4 right angles, 2 sets of parallel
lines and 2 lines of symmetry.
Parallelogram is a cousin.
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This is an ordinary garden-variety circle.
chord
radius
diameter
It has 360 degrees. Its circumference is found
by multiplying the diameter or the radius squared
by 3.14 or 22/7.
circumference
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Circles have many lines of symmetry because they
are all the same distance from the mid-point of
the circle which makes them appear round.
Which came first, the circle or its central
angles?
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Describe each plane figure by line, angle,
symmetry and shape.
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Now that thats over, lets talk SOLID geometry!
Dude, I mean 3-D stuff.
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Base
Is this not a 3-D cube? Yes, this is a 3-D
cube. Two bases Eight vertices Twelve edges All
congruent faces Cube, Cube, Congruent Cube
Oh-----------------h
E d ge
Base
vertices
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To find the volume of a cube, multiply the width
times the length times the width with this
formula V W x L x H
height
height
width
length
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Is this not a rectangular prism? Yes, this is a
rectangular prism. Two bases, Eight right angle
vertices, 12 congruent edges, Two parallel bases!
Oh--------h
A present, for me?
Find the volume just like a cube.
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Is this not a triangular prism? Yes, this is a
triangular prism. Four vertices, six edges,one
triangular base, four congruent faces.
Oh--------h
Find my volume with ½ base times length times
height or !/2blh
height
length
base
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Other triangle prisms
Square pyramid
Pentagonal pyramid
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Is this not a cylinder? Yes this is a
cylinder? Got no vertices Got no edges Got two
bases
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A Wm. Blaine Beam Production
Produced by christine S. Grigg