Getting Started 
Misconception/Error The student is unable to draw a triangle with the given conditions. 
Examples of Student Work at this Level The student:
 Draws a triangle with incorrect angle or side measures.
 Draws a figure that is not a triangle (e.g., an open figure with three sides).Â

Questions Eliciting Thinking What are the features of a triangle?
What is an included angle?
What strategies would you use to draw a triangle given the measures of two sides and the included angle? Where is a good place to begin drawing?
How would using the ruler and protractor help you draw a triangle with the given conditions? 
Instructional Implications Define a triangle as a polygon with three sides. Make clear that an open figure with three sides is not a triangle (since it is not a polygon). Describe the parts of a triangle and how to name them (e.g., the vertices, sides, and angles). Be sure the student understands how to measure angles.
Provide the student with a manipulative such as or software such as Geogebra (www.geogebra.org) to assist in building triangles with given conditions. The student may be more adept in drawing triangles with given conditions after working with a handson manipulative or software.
Guide the student to draw a triangle with given conditions. Assist the student in using the ruler and protractor to construct the triangle. Explain that a good way to begin is by drawing a working line and â€śbuildingâ€ť the triangle on it. Ask the student to measure one of the given lengths (e.g., 1 in.) on the working line and label this as . Using point E as a vertex, have the student measure and draw . Next, have the student measure and mark the endpoint of on the other side of using the second given length. Then have the student draw to form the third side of the triangle. If needed, model how to properly label the angles and sides of a triangle. Finally, have the student verify that the drawn triangle fits the given conditions.
Provide additional opportunities for the student to draw triangles when given the measures of two sides and their included angle. 
Moving Forward 
Misconception/Error The student is unable to correctly determine if the given conditions form a unique triangle. 
Examples of Student Work at this Level The student is able to draw a triangle with the given conditions, but says it is possible to draw a different triangle with the same conditions. For example, the student states:
 The triangles are not the same (e.g., congruent) because they are oriented differently.Â
 The shapes will be similar.
 A new triangle can be drawn if the same measurements are put on different sides.Â

Questions Eliciting Thinking What do you mean by â€śthe shapes will be similar?â€ť
What would be different in the new triangle?
Can you change the measure of an angle without affecting the length of its opposite side?
Can you change the measure of a side without affecting the size of the opposing angle? 
Instructional Implications Use tracing paper to demonstrate to the student that two triangles can be oriented differently but still be the same (e.g., congruent). If the student did not attempt to construct a second triangle with the given conditions, ask the student to do so. Have the student confirm that the measures of the sides and angles correspond to the given measures. Then have the student use tracing paper to determine if the triangles are congruent.
Another option is to have the student imagine changing the length of side and the effect this would have on the measure of the opposite angle, . Guide the student to observe that changing the measure of the side of a triangle causes the measure of the opposite angle to change as well. Since must measure 100Â°, the length of the opposite side cannot take on a different measure.
Provide the student with another set of SAS conditions, and encourage the student to further experiment and confirm this conclusion. 
Almost There 
Misconception/Error The student does not adequately explain why the given conditions form a unique triangle. 
Examples of Student Work at this Level The student is able to draw a triangle with sides of the given lengths and says it is not possible to draw more than one triangle with these conditions, but does not provide a clear explanation. The student explains:
 The triangles will be the same.
 You can only draw the triangle one way.
 The angles (or sides) would all be the same.
 You are not able to change one angle or side without changing another side or angle.

Questions Eliciting Thinking Can you explain why the triangles will be the same?
Are there some sets of conditions that do not determine a unique triangle? 
Instructional Implications Help the student confirm his or her conclusion by constructing another triangle with the same three measurements. Have the student directly measure the angles and compare the measurements to the angle measures of the original triangle. Guide the student in discussing the relationship among the sides and angles within a triangle.
Model constructing a triangle with sides and included angle of the given measures as described in the Getting Started Instructional Implications. Show the student that the length of the third side is determined by the given angle measure. Explain that this ensures that there is only one way to draw the triangle. Model a concise explanation using mathematical terminology. For example, if is 100Â°, and its side lengths are 1 inches and 2 inches in length, all three vertices of the triangle have been determined. This means there is only one possible length for the third side, and a unique triangle is determined. 
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 is able to draw a triangle with the given angle and included side measures and says it is not possible to draw more than one triangle with these conditions. The student explains in terms of:
 The uniqueness of the third side (see Instructional Implications for Almost There).
 The relationship between the length of a side and the opposite angle measure.

Questions Eliciting Thinking If sides and were switched, would the triangle be congruent to the original? Explain.
What does â€ścongruentâ€ť mean?
Can you describe your strategy in drawing triangle DEF?
How important was accuracy and precision in completing this task? 
Instructional Implications Pair the student with a Moving Forward partner to share strategies for drawing triangles.
Consider implementing the MFAS tasks Drawing Triangles ASA, Drawing Triangles AAA, Drawing Triangles SSA, Drawing Triangles AAS, or Drawing Triangles SSS (7.G.1.2). 