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 2000

Use the segment below to complete each of the following constructions.

Complete the following in the answer box below:

  • Using segment AB, construct equilateral triangle ABC. Use mathematics to explain the process you used to construct the triangle. Use words, symbols, or both in your explanation.
     
  • Construct circle O so that ΔABC is inscribed in circle O. Use mathematics to explain your process. Use words, symbols, or both in your explanation.
     

The following 9 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 shows little application of a reasonable strategy. The midpoint of AB is found by incorrectly substituting measurement for construction. The student uses that measurement of half of AB to form the other side of isosceles ΔABC, whereas the question required an equilateral triangle with all sides congruent to AB. The student constructs an isosceles right triangle, but does inscribe that triangle in a circle. Correct representations in the response are missing, except for a circle circumscribing the isosceles triangle. The explanation reveals serious flaws in reasoning and is based on measurement rather than construction. This response demonstrates a minimal understanding and analysis of the problem.


Anchor Paper #2

image of student response

Score for Anchor Paper #2: Rubric Score 1

Annotation: There is no application of a reasonable strategy in this response. The student states that he/she "measured the base" and "drew the sides the same length as the whole base," which indicates measurement was used to draw the triangle. Although the response later indicates "I made the circle by using a compass," the circle's irregularity indicates it was hand-drawn. These two explanations reveal serious flaws in reasoning because measurement is used instead of construction. The correct representations are missing. Except for the faulty hand-drawn circle, the only representation is the triangle that was not constructed, but created by measurement. This response demonstrates minimal understanding and analysis of the problem because the student uses measurement throughout the response.


Anchor Paper #3

image of student response

Score for Anchor Paper #3: Rubric Score 1

Annotation: This response provides a good explanation for how to draw an equilateral triangle with a given side AB using measurement; however, this strategy is inappropriate because the problem requires construction, not measurement. The explanation and representation are flawed because of the substitution of measurement for construction. There is no evidence of a construction of a circle circumscribing ΔABC, nor is there any construction for finding the center of the circle. There are some faint marks indicating that parts of a hand-drawn circle might have been attempted, but there is no explanation in words or arc marks. This response indicates minimal understanding and analysis of the problem.


Anchor Paper #4

image of student response

Score for Anchor Paper #4: Rubric Score 2

Annotation: This student states, "I first measured the length of AB. Next I drew a perpendicular line through the center of AB." The response continues with other indications of measurement being substituted for the appropriate required strategy of construction. There is no evidence of arc marks to show construction was used, nor is there any explanation for the possibility of patty paper being used. The only mention of construction is "This gave me the radius for my circle. I then drew …using a compass." The explanation and representations are plausible for measurement, not construction. There is evidence of a good understanding of the mathematical principles throughout the response, but without the required construction, this response demonstrates only a conceptual understanding and analysis of the problem.


Anchor Paper #5

image of student response

Score for Anchor Paper #5: Rubric Score 2

Annotation: This response indicates a conceptual understanding and analysis of the problem. The representation is incomplete. The constructed triangle is equilateral with arc marks to indicate a reasonable strategy. Multiple attempts at locating the center of the circle by trial and error are evident. The circle's center was found but not by construction techniques and does not reveal a good mathematical principle for finding the center, so the overall strategy employed is an incomplete correct strategy.


Anchor Paper #6

image of student response
image of student response

Score for Anchor Paper #6: Rubric Score 3

Annotation: This response indicates application of a reasonable strategy, but has an error in the representation. The representation is essentially correct. The triangle and the circle, as well as the center point for the circle, were fully constructed. Arc marks serve as support for the correct strategy of construction. The written explanation also supports the correct strategy of construction techniques, although the student appears to have confused the terms protractor with compass, and perpendicular bisector with angle bisector. (We can assume the correct compass tool was used because "point" and "pencil" were mentioned.) However, an error, possibly in marking the length of AB, led to an isosceles triangle rather than an equilateral triangle. The correct strategy for finding the center of the triangle by finding the intersection of the angle bisectors was employed, but the incorrect triangle led to a circle that does not have all three points of the triangle located on the circle. This student has employed a completely correct strategy, fully explained, but has made an error in the application of that strategy. Overall, the response demonstrates a clear understanding and analysis of the problem.


Anchor Paper #7

image of student response

Score for Anchor Paper #7: Rubric Score 3

Annotation: This response indicates an application of a reasonable strategy to construct a triangle. The representation is essentially correct. Clearly visible arc marks support the strategy of construction techniques used to construct the triangle, and the written explanation for the triangle confirms the use of construction techniques. However, there are no arc marks to support the strategy of constructing the perpendicular bisectors to find the center of the circle. Written explanation for the circle does not indicate another strategy for construction. The student conveys the mathematical principle that "where the perpendicular bisectors meet is the center of the circle," an acceptable strategy for this problem. Overall, the response demonstrates a clear understanding and analysis of the problem.


Anchor Paper #8

image of student response

Score for Anchor Paper #8: Rubric Score 4

Annotation: This response indicates application of a reasonable strategy that leads to a correct solution of the problem. The representation is correct, with all arc marks present to clearly explain and support the construction techniques used to construct the triangle, the center for the circle, and the circle. Written explanation provides confirmation of the correct strategy used to support the solution. The response demonstrates a complete understanding and analysis of the problem.


Anchor Paper #9

image of student response

Score for Anchor Paper #9: Rubric Score 4

Annotation: This response indicates application of a reasonable strategy that leads to a correct solution of the problem. The representations are correct, with all arc marks present to clearly explain and support the construction techniques used to construct the triangle, the center for the circle, and the circle. No written explanation is necessary, as having all arc marks present will fully support the correct solution. The response demonstrates a complete understanding and analysis of the problem.


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/2000_214_geo31.xml
Resources for 2.1.4:
Skill Statements | PUBLIC RELEASE ITEMS | Lesson Plans |