Getting Started 
Misconception/Error The student sketches or draws rather than constructs. 
Examples of Student Work at this Level The student:
 Sketches an angle that appears congruent to .
 Uses a protractor to measure and draw a congruent angle.
 Uses a compass to measure BC, then constructs two points each a distance of BC from a point E, and draws an angle containing the points.

Questions Eliciting Thinking What is the difference between drawing and constructing?
When doing a geometric construction, what tools are typically used?
What is a disadvantage of using a protractor? Is a compass potentially more accurate? 
Instructional Implications Explain to the student the difference between drawing and constructing. Show the student the tools traditionally used in geometric constructions and explain the purpose of each. Be sure the student understands that a protractor is not one of the tools used in traditional geometric constructions.
Guide the student through the steps of constructing an angle congruent to a given angle. Have the student label the congruent angle , as given in the instructions. Have the student remove any unnecessary marks or marks made in error from his or her paper. Ask the student to write out the steps of the construction and keep them for future reference. Provide additional opportunities to construct angles in isolation or as part of other constructions such as the construction of a triangle. 
Moving Forward 
Misconception/Error The student attempts the construction but makes a significant error. 
Examples of Student Work at this Level The student constructs a working line, marks point E on the working line, and:
 With point E as the center, makes an arc congruent to one already drawn on . The student is unable to complete the construction and simply draws .
 Makes an arc centered at point E with a radius of BC. The student then measures AC with the compass and uses this radius to locate point D.

Questions Eliciting Thinking You started this construction correctly. How did you determine the radius of this arc?
Are A and C the same distance from B? How can you check this?
How did you determine where to locate ? 
Instructional Implications Explain to the student the need to precisely locate points in constructions, and that points can be precisely located at the intersection of two construction marks. Guide the student to begin angle constructions with a working line and to use the compass to measure needed lengths.
Guide the student through the steps of constructing an angle congruent to a given angle. Have the student label the congruent angle , as given in the instructions. Have the student remove any unnecessary marks or marks made in error from his or her paper. Ask the student to write out the steps of the construction and keep them for future reference. Provide additional opportunities to construct angles in isolation or as part of other constructions such as the construction of a triangle.
Challenge the student to construct an angle whose measure is the sum of two given angles. Draw the given angles so that they do not share a vertex or side. 
Almost There 
Misconception/Error The student correctly completes the construction but does not label the construction or leaves unnecessary marks on the paper. 
Examples of Student Work at this Level The student:
 Correctly constructs an angle congruent to but does not label it as . The student may not label the constructed angle at all or labels it as .
 Correctly constructs and labels but leaves several unnecessary or unused construction marks on the construction.
Note: The student whose work is shown above also attempted to justify the construction with SAS (rather than SSS). 
Questions Eliciting Thinking Where is in your construction?
What are these arcs for? Did you use them in your construction? 
Instructional Implications Ask the student to label the congruent angle , as given in the instructions and to remove any unnecessary marks or marks made in error from his or her paper.
Ask the student to highlight the two triangles formed in the construction and to justify the use of SSS.
Challenge the student to construct angles whose measures are 2(m), (m), and (m). Ask the student to appropriately label each constructed angle and to remove any unnecessary construction marks. 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student uses a straightedge to construct a working line. The student marks vertex E on the working line and then uses the SSS method to construct . All needed construction marks are shown and no unnecessary marks remain. The student correctly labels the constructed angle as . 
Questions Eliciting Thinking How can you justify your construction? How do you know that it results in an angle that is congruent to the given one? 
Instructional Implications If the triangle congruence theorems have been introduced, ask the student to write up a justification for the congruent angle construction. Then ask the student to construct a triangle congruent to a given triangle using the SSS method. Ask the student to explain the similarities in the constructions.
Challenge the student to construct angles whose measures are 2(m), (m), and (m). Ask the student to appropriately label each constructed angle and to remove any unnecessary construction marks. 