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# MAFS.912.G-CO.4.12

Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line.

Subject Area: Mathematics
Domain-Subdomain: Geometry: Congruence
Cluster: Level 2: Basic Application of Skills & Concepts
Cluster: Make geometric constructions. (Geometry - Supporting Cluster) -

Clusters should not be sorted from Major to Supporting and then taught in that order. To do so would strip the coherence of the mathematical ideas and miss the opportunity to enhance the major work of the grade with the supporting clusters.

Date Adopted or Revised: 02/14
Date of Last Rating: 02/14
Status: State Board Approved
Assessed: Yes

### Remarks/Examples

Geometry - Fluency Recommendations

Fluency with the use of construction tools, physical and computational, helps students draft a model of a geometric phenomenon and can lead to conjectures and proofs.

### TEST ITEM SPECIFICATIONS

• Item Type(s): This benchmark may be assessed using: MC item(s)
• Also assesses:

MAFS.912.G-CO.4.13

• Assessment Limits :
Constructions are limited to copying a segment; copying an angle;
bisecting a segment; bisecting an angle; constructing perpendicular
lines, including the perpendicular bisector of a line segment;
constructing a line parallel to a given line through a point not on the
line; constructing an equilateral triangle inscribed in a circle;
constructing a square inscribed in a circle; and a regular hexagon
inscribed in a circle.

Constructions are limited to the use of a formal compass and a
straightedge.

Items should not ask student to find values or use properties of the
geometric figure that is constructed.

• Calculator :

Neutral

• Clarification :
Students will identify the result of a formal geometric construction.

Students will determine the steps of a formal geometric construction

• Stimulus Attributes :
Items may be set in a real-world or mathematical context.
• Response Attributes :
Items may require the student to justify why a construction results in
the geometric figure.

Items may require the student to use or choose the correct unit of
measure.

Items may require the student to provide steps for a construction.

### SAMPLE TEST ITEMS (1)

• Test Item #: Sample Item 1
• Question:

Ruben carries out a construction using Triangle BC. Click the play button to see a part of his construction,

What will be the result of Ruben's construction?

• Difficulty: N/A
• Type: MC: Multiple Choice