Fourth Grade Geometry

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Fourth Grade Geometry

• Fun with Native American Art

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Geometry Objectives

• (4.8) Geometry and Spatial Reasoning
• A. Identify right, acute, and obtuse angles
• B. Identify models of parallel and
  perpendicular lines
• C. Describe shapes and solids in terms of
  vertices, edges, and faces
• (4.9) Geometry and Spatial Reasoning
• A. Demonstrate translations, reflections, and
  rotations

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Acute Angles

• Can you identify an acute angle on this Native
  American work of art?

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Acute Angle

• Highlighted in red shows one example of an acute
  angle in this picture.
• An acute angle measures less than 90 degrees.

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Obtuse Angles

• Can you identify an obtuse angle in this Native
  American art?

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Obtuse Angle

• Highlighted in red is one of the obtuse angles
  found in this picture.
• An obtuse angle measures more than 90 degrees.

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Right Angles

• Can you identify a right angle in this Native
  American art?

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Right Angles

• Highlighted in red shows one of many right angles
  in this picture.
• A right angle measures exactly 90 degrees.

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Is this an example of a reflection, translation
or rotation?
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Rotation!

• The Native American pottery rotated through each
  of the four quadrants.

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Look at this picture!

• Can you identify all the pictures within in the
  squares that have symmetry?

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Parallel Lines

• Can you identify the parallel lines in this
  Native American art?

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Parallel Lines

• Highlighted in red is an example of parallel
  lines
• Parallel lines are two or more lines that are in
  the same plane but do not intersect.

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Perpendicular Lines

• Can you identify perpendicular lines in this
  Native American art?

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Perpendicular Lines

• Highlighted in red is a set of perpendicular
  lines in this picture.
• Perpendicular lines are two lines in the same
  plane that meet at right angles.

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Name this polygon
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Name this polygon!

• Octagon
• An octagon is a polygon with eight sides.
• Can you think of other objects around your
  community that have the same number of sides like
  an octagon?

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A stop sign!

• A stop sign is also an octagon. It has eight
  sides.