September 6, 2013 1) Sit. 2) Materials out. 3) Backpacks away. 4) Do Now SILENTLY.

September 6, 20131) Sit. 2) Materials out. 3) Backpacks away. 4) Do Now SILENTLY. Learning Goal: • IWBAT to determine whether given side lengths form triangles and solve for unknown angles in triangles. Homework: • HW 3.2: Triangle Inequality Worksheet • HW 3.3A: Triangle Sum Theorem Worksheet ------------------------------------------------------------------- Do Now: • Find the measure of the unknown angles shown below.

Agenda: • Do Now (10 min) • Explore Triangle Inequalities (15 min) • Triangle Inequality Theorem (30 min) • Constructing Triangles (15 min) • Triangle Proofs (15 min) • Whiteboard Activity (30 min) • Closure (5 min)

Triangle Experiment • Each pair will receive straws of different lengths • Select three straws with the given lengths and test whether the straws form a triangle. • Check off the “Yes” or “No” box.

Triangle Experiment • Try to find some common characteristics for the sets of side lengths that DO form a triangle. • Try to find some common characteristics for the sets of side lengths that DO NOT form a triangle. • Come up with a rule that can predict whether three side lengths will form a triangle.

Triangle Inequality Theorem

Construct a Triangle • Construct a triangle that has side lengths 3 cm, 4 cm, and 5 cm. • Teacher will demonstrate to the class how to construct the triangle. • You can also follow the steps presented in the handout. • Construct a triangle with the following lengths. Some sets of given lengths will form triangles while others will not. • 1 cm, 1cm, 2 cm • 4 cm, 5cm, 2 cm

Review Triangle Theorems

Triangle Proofs • Given m<ABC = 30 m<BCA = 20 Prove m<DAE = 130 D B A E C

Triangle Algebra Activity • Students break up into groups of 3 or 4. Groups have been predetermined. Each group receives a whiteboard, marker, and eraser. • Teacher will present practice exercises about triangles on the board. • Your teams have 2 minutes to solve the problem and write the answer on the whiteboard with its justification. • The correct answer receives 1 point. The correct justification receives an additional point.

Geometry Period 2 Teams • Green Team • Ben M. • Kathy M. • Christian V. • Brisya C. • Purple Team • Linda • Jovanny H. • Adolfo G. • Justlene S. • Red Team • George O. • Mayra R. • Charles L. • Ashley T. • Yellow Team • Oscar E. • Jazmin A. • Nancy L. • Orange Team • Ben L. • Susana A. • Abel P. • Blue Team • Jose L. • Carina A. • Jackie D. • Miguel B.

Geometry Period 4 Teams • Green Team • Veronica S. • Oscar S. • Lorena G. • Alfonso M. • Purple Team • James L. • Lee Ann Q. • Mirna A. • Thea Q. • Red Team • Dennise P. • Amanda V. • Seth F. • Javier G. • Yellow Team • Jesus R. • Ariana P. • Leslie V. • Erick M. • Orange Team • Christina G. • Derek A. • Yuleni V. • Blue Team • Angie Z. • Miranda D. • Arthur D. • Sydney G.

Geometry Period 6 Teams • Green Team • Christina R. • GeovanniB. • Oscar G. • Sabrina L. • Purple Team • Alexis A. • Deborah H. • Sabrina O. • Cristian B. • Red Team • Freddy A. • Anthony S. • Hannya O. • Ashley L. • Orange Team • Steven P. • Wendy G. • Abel P. • Leslie H. • Yellow Team • Paulina C. • Martin R. • Melissa R. • Jonathan T. • Blue Team • Jose S. • Jailene L. • Abigail G. • Andy H.

Exercise #1 • Find the measure of the unknown angle shown below.

Triangle Theorem Masters • Period 2 • Miguel B. • Jose L. • Jackie D. • Carina • Period 3 • Period 1 • Period 5 • Period 6 • Oscar G. • Christina R. • Sabrina L. • Geo B. • Period 4 • Jesus R. • Ariana P. • Leslie V. • Eric M.

Closure Take a moment to response to the following prompts on a flashcard. • Why do the angles of any triangle add up to 180 degrees? • The angles of any triangle add up to 180 degrees because ___________________________ . • What conditions must three sides satisfy in order for the sides to form a triangle? • In order for sides to form a triangle, _____________________ .

September 6, 2013 1) Sit. 2) Materials out. 3) Backpacks away. 4) Do Now SILENTLY.