School Improvement in Maryland
Public Release Item Scoring Information Return

Goal 2 Geometry, Measurement, And Reasoning

Expectation 2.1 The student will represent and analyze two- and three-dimensional figures using tools and technology when appropriate.

Indicator 2.1.4 The student will construct and/or draw and/or validate properties of geometric figures using appropriate tools and technology.

Assessment Limits:

  • “Validate properties” in this indicator, means justifying solutions using definitions, mathematical principles and/or measurement.
  • Students may use a compass, straightedge, patty paper, a MiraTM, and/or a mirror as construction tools. Using a ruler or protractor cannot be part of the strategy.
  • Students may use a compass, ruler, patty paper, a MiraTM, a mirror and/or a protractor as drawing tools.
  • It is acceptable to do a construction when the item asks for a drawing.
  • Paper folding and the use of MirasTM and mirrors are appropriate methods for representing, constructing, and/or analyzing figures, and their use must be referenced.
  • Constructions and drawings are limited to the two-dimensional relationships listed in 2.1.1.

Extended Constructed Response (ECR) Item - Released in 2002

The floor plan for an office in a new building is shown below. The interior designer wishes to place a desk so that it is equidistant from all the walls in the office.

Complete the following in the answer box below:
  • Use construction techniques to locate the point where the desk should be.
  • Explain the steps you used in your construction. Use words, symbols, or both in your explanation.
  • Use mathematics to justify that the location of the desk is equidistant from the walls of the office.

The following 8 Anchor Papers represent a range of score points and are used in conjunction with the rubrics to assess student responses.

Anchor Paper #1

image of student response

Score for Anchor Paper #1: Rubric Score 1

Annotation: This response demonstrates a minimal understanding and analysis of the problem. The student locates the correct point representing desk placement. However, arc marks and an explanation reveal that the correct strategy of locating the intersection of angle bisectors is not employed. The explanation "to find points that were equidistant from a vertex and a midpoint of each wall in to opposite locations" is an inappropriate strategy and does not support all the arc marks present. A minimal understanding of equidistance is present in the strategy employed as well as the attempt to justify by using "the same measure for each point drawn."


Anchor Paper #2

image of student response

Score for Anchor Paper #2: Rubric Score 1

Annotation: This response demonstrates a minimal understanding and analysis of the problem. The representation is incorrect. The student is unable to locate the point representing the correct desk placement. Compass arc marks and explanation reveal construction of perpendicular bisectors to locate the midpoint of each side of the triangle — an inappropriate strategy. The student does not provide any explanation of how the center of the circle was located, but erasure marks indicate that the student narrowed down the location of the center and "guessed." This response lacks the correct strategy of the application of angle bisectors but does demonstrate an understanding of equidistance in the attempt at justification. The center of the circle representing desk placement is equidistant from each of the three midpoints.


Anchor Paper #3

image of student response

Score for Anchor Paper #3: Rubric Score 2

Annotation: This response demonstrates a conceptual understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. Partially erased compass arc marks are present, but those arc marks indicate the construction of perpendicular bisectors, an inappropriate strategy. The explanation reveals that the student understands the correct concept of finding the intersection of angle bisectors, but, without any demonstration of appropriate construction, the response indicates application of an incomplete correct strategy. The student fails to provide any justification.


Anchor Paper #4

image of student response

Score for Anchor Paper #4: Rubric Score 2

Annotation: This response demonstrates a conceptual understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. There are no compass arc marks to reveal construction. The explanation demonstrates that the student understands the correct concept of finding the intersection of angle bisectors; however, without any appropriate construction or explanation of the appropriate use of construction tools, the response indicates application of an incomplete correct strategy. "Point A is equidistant from all of the walls of the office because it is the center of the incenter" (defined as: the center of an inscribed circle as well as the intersection of the angle bisectors of a triangle or regular polygon) provides some explanation of a correct strategy as well as justification.


Anchor Paper #5

image of student response

Score for Anchor Paper #5: Rubric Score 3

Annotation: This response demonstrates a clear understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. Explanation and compass arc marks fully indicate application of a complete correct strategy of constructing angle bisectors; however, the student fails to provide any justification.


Anchor Paper #6

image of student response

Score for Anchor Paper #6: Rubric Score 3

Annotation: This response demonstrates a clear understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. A fully developed explanation reveals a correct strategy of constructing angle bisectors using patty paper, an acceptable construction tool. However, the student fails to provide any justification.


Anchor Paper #7

image of student response

Score for Anchor Paper #7: Rubric Score 4

Annotation: This response demonstrates a complete understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. The compass arc marks and explanation illustrate a complete correct strategy of constructing angle bisectors. "I drew a circle around it (the point), and the circle perfectly fit in the triangle. I measured from vertical point to each wall, and they were equidistant" provides full justification. All radii of a circle are of equal measure so a circle that touches all three walls would have its center at a point equidistant from all three walls. The student claims to have also measured the distance from the point to all three walls. While the student makes an error in terminology, referring to the perpendicular distance as "vertical point," the understanding is clearly present.


Anchor Paper #8

image of student response

Score for Anchor Paper #8: Rubric Score 4

Annotation: This response demonstrates a complete understanding and analysis of the problem. The representation is correct. The student locates the point indicating correct placement of the desk. The explanation and compass arc marks fully explain a complete correct strategy of constructing angle bisectors. Justification is provided in the statement "any point on the angle bisector is equidistant from both sides of the angle."


Extended Constructed Response (ECR) Rubric

Print: Scoring Rubric (pdf)
Score 4

The response indicates application of a reasonable strategy that leads to a correct solution in the context of the problem. The representations are correct. The explanation and/or justification is logically sound, clearly presented, fully developed, supports the solution, and does not contain significant mathematical errors. The response demonstrates a complete understanding and analysis of the problem.

Score 3

The response indicates application of a reasonable strategy that may or may not lead to a correct solution. The representations are essentially correct. The explanation and/or justification is generally well developed, feasible, and supports the solution. The response demonstrates a clear understanding and analysis of the problem.

Score 2

The response indicates an incomplete application of a reasonable strategy that may or may not lead to a correct solution. The representations are fundamentally correct. The explanation and/or justification supports the solution and is plausible, although it may not be well developed or complete. The response demonstrates a conceptual understanding and analysis of the problem.

Score 1

The response indicates little or no application of a reasonable strategy. It may or may not have the correct answer. The representations are incomplete or missing. The explanation and/or justification reveals serious flaws in reasoning. The explanation and/or justification may be incomplete or missing. The response demonstrates a minimal understanding and analysis of the problem.

Score 0

The response is completely incorrect or irrelevant. There may be no response, or the response may state, “I don't know.”

Explanation refers to the student using the language of mathematics to communicate how the student arrived at the solution.

Justification refers to the student using mathematical principles to support the reasoning used to solve the problem or to demonstrate that the solution is correct. This could include the appropriate definitions, postulates and theorems.

Essentially correct representations may contain a few minor errors such as missing labels, reversed axes, or scales that are not uniform.

Fundamentally correct representations may contain several minor errors such as missing labels, reversed axes, or scales that are not uniform.

Last Revised 8/16/00

/share/clg/xml/public_release/mathematics/2002_214_geo31.xml
Resources for 2.1.4:
Skill Statements | PUBLIC RELEASE ITEMS | Lesson Plans |