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 figure that is not a triangle (e.g., an open figure with three sides).
 Draws a triangle with incorrect angle or side measures.

Questions Eliciting Thinking What are the features of a triangle?
What is an included side?
What strategies would you use to draw a triangle given two angles and an included side? 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 the given length on the working line to locate side . Using the endpoints of as vertices, have the student draw A and B using the given angle measures. Next, have the student extend the sides of these angles until they intersect in the third vertex of the triangle, Point C. 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 angles and their included side. 
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.
 The angle stays the same but the sides can change.
 The size of the third angle can be changed.
The student is able to draw a triangle with the given conditions, but does not explain if it is possible to draw another triangle.

Questions Eliciting Thinking 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 length of the nonincluded sides without changing the length of the third side? 
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 side 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 measure of C and how the length of the opposite side, , is affected. Guide the student to observe that changing the measure of an angle in a triangle causes the length of the opposite side to change as well. Since the opposite side must be 11 cm, C cannot take on a different measure.
Provide the student with another set of ASA 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 a side and two angles of the given measures 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:
 You can only draw the triangle one way.
 The angles would all be the same.
 The remaining side must be the same as the first triangle.

Questions Eliciting Thinking Why do you need more than just all three angles to be the same for the triangles to be identical?
What conditions must be true for triangles to be congruent?
What do you mean by â€śyou can only draw the triangle one way?â€ť
Can you change an angle measure without affecting the length of the opposite side?
Can you change just two side lengths and keep all three angle measures the same?
What do you mean by â€śthe remaining side must be the same as the first triangle?â€ť 
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 angles and included side of the given measures as described in the Getting Started Instructional Implications. Show the student there is only one point of intersection for the third vertex when two angles and the included side are given. Explain that this ensures that there is only one way to draw the triangle. Model a concise explanation using mathematical terminology. For example, if the side on the working line is which is 11cm in length, m A is 55Â°, and m B is 85Â°, there is only one point where the other sides of A and B can intersect. This means there is only one possible location for vertex C, 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 vertex (see Instructional Implications for Almost There).
 The relationship between the length of a side and the opposite angle measure.

Questions Eliciting Thinking If angles A and B 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 ABC?
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 SAS, Drawing Triangles AAA, Drawing Triangles SSA, Drawing Triangles AAS, or Drawing Triangles SSS (7.G.1.2). 