Mathematics (2019) Grade(s): 7

MA19.7.18

Construct geometric shapes (freehand, using a ruler and a protractor, and using technology), given a written description or measurement constraints with an emphasis on constructing triangles from three measures of angles or sides, noticing when the conditions determine a unique triangle, more than one triangle, or no triangle.

Unpacked Content

Knowledge

Students know:
  • if three side lengths will create a unique triangle or no triangle.

Skills

Students are able to:
  • freehand, draw geometric shapes with given conditions.
  • Using a ruler and protractor, draw geometric shapes with given conditions.
  • Using technology, draw geometric shapes with given conditions.
  • Construct triangles from three measures of angles or sides.
  • Identify the conditions that determine a unique triangle, more than one triangle, or no triangle.

Understanding

Students understand that:
  • from their experiences with constructions, what conditions are necessary to construct a triangle.
  • only certain combinations of angle and side measures will create triangles.
  • Constructing a triangle requires a specific relationship between the legs of the triangle and a specific sum between the angles of the triangle.

Vocabulary

  • Construct
  • protractor
  • Angle measures
  • Constraints
  • Acute triangle right triangle
  • obtuse triangle
  • isosceles triangle
  • Scalene triangle
  • Equilateral triangle
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