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

Score for Anchor Paper #1: Rubric Score 1

Annotation: This response demonstrates minimal understanding and analysis of the problem. While this student recognizes that congruent alternate interior angles prove parallel lines, the stated angles are congruent, but without any proof. The student also asserts, and clarifies by the diagram markings, "E is a vertical angle" which could be both a correct step and a justification for an appropriate triangle proof. However, with only the indicated angles, there is no evidence of a triangle strategy. No attempt to justify a rectangle is present.

Score for Anchor Paper #2: Rubric Score 1

Annotation: This response demonstrates minimal understanding and analysis of the problem. Although the strategy AAS (angle-angle-side) is flawed, the student has some understanding that proving the triangles are congruent could be used to prove parallel lines. After establishing isosceles triangles with congruent sides and a congruent vertex angle, the statement "Angle A is congruent to angle C" can be asserted, but the student lacks any support for this strategy. The unsupported statements "A rectangle has 4 parallel sides" and "AB is parallel to DC, AD is parallel to BC" convey some understanding of the properties of rectangles. "The diagonals intersect and are congruent" provides justification for a rectangle.

Score for Anchor Paper #3: Rubric Score 2

Annotation: This response demonstrates conceptual understanding and analysis of the problem. The student attempts to prove parallel lines by proving congruent triangles and using congruent alternate interior angles. The justifications are flawed. While the student does not state what congruent pairs of sides were used in the SAS (side-angle-side) proof, the diagram markings make this clear. The student does not justify a rectangle. "ABCD is a rectangle because all of the angles are the same" fails to identify the referenced angles, and the only marked congruent angles in the diagram are BEA and DEC.

Score for Anchor Paper #4: Rubric Score 2

Annotation: This response demonstrates conceptual understanding and analysis of the problem. The student employs an appropriate SAS (side-angle-side) strategy to prove congruent triangles. An error occurs in the statement "DB BE," but this is considered minor due to the diagram markings. The student then incorrectly attempts to establish parallel lines by congruent corresponding sides rather than by congruent alternate interior angles. The attempt to justify a rectangle is incomplete. "ABCD is a rectangle because AB DC" and "point A is the same distance from point D, and point B is the same distance from point C, since AC DB" provide only partial justification of a rectangle.

Score for Anchor Paper #5: Rubric Score 3

Annotation: This response demonstrates clear understanding and analysis of the problem. In the SAS (side-angle-side) proof, the student should have provided the justification of CPCTC (congruent parts of congruent triangles are congruent) for "DCE must be to BAE." Instead, the response states that the angles are congruent "because they (the triangles) are congruent." In establishing the second set of parallel lines, the student omits the parts utilized for proving the second pairs of triangles congruent by SAS (side-angle-side). However, the strategy is clearly evident from the first SAS proof. The student gives an incomplete justification "opposite sides are parallel."

Score for Anchor Paper #6: Rubric Score 3

Annotation: This response demonstrates clear understanding and analysis of the problem. The student shows clear evidence of an appropriate strategy to prove parallel lines, but the proof has errors. While the student attempts to reorder the steps in the SAS (side-angle-side) proof, the congruent corresponding angles should be given after the triangles are proven congruent. The correct justification for "A C" and "D B" should be CPCTC (congruent parts of congruent triangles are congruent), and the justification for "AB // DC" should be the converse of alternate interior angles theorem. The justifications are switched for these two steps. Justification for a rectangle ("ABCD is a rectangle because the diagonals are congruent to each other. The diagonals also bisect each other.") is given.

Score for Anchor Paper #7: Rubric Score 4

Annotation: This response demonstrates complete understanding and analysis of the problem. The student successfully proves parallel lines. All statements needed in the SAS (side-angle-side) proof have correct justification, and the student correctly proves parallel lines by the converse of alternate interior angles theorem. The statement "AC and BD are the diagonals of ABCD. Since these two bisect each other…the two diagonals are also congruent" provides full justification for a rectangle.

Score for Anchor Paper #8: Rubric Score 4

Annotation: This response demonstrates complete understanding and analysis of the problem. All the information proving the ironing board is parallel to the floor and defining a rectangle is clearly and logically presented. The student uses an indirect proof ("The ironing board is parallel to the floor because if ABCD is a rectangle, it must be parallel to the floor. In order to be a rectangle, you must have two sets of parallel sides.") to assert parallel lines. The response then establishes a rectangle ("ABCD is a rectangle because it has two bisecting and congruent diagonals.") from the given information.

Additional Scored Student Responses