     Put your 11.1 Worksheet ready for a stamp.

Take out a protractor.

What does it mean for polygons to be similar?

Find the scale factor from the smaller shape to the larger shape in the figure above.

◦ Give a counterexample to each statement. (Can be in the form of a picture or explanation.) Two polygons that have corresponding angles congruent must be similar.

  11.2 WS is due Monday/Tuesday Bring your raffle tickets for an auction a week from today.

   Discover shortcut methods for determining similar triangles Use proportions to find measures in similar figures Use problem solving skills

   We concluded that you must know about both the angles and the sides of two polygons in order to make a valid conclusion about their similarity.

However, triangles are unique. Remember there were 4 shortcuts for triangle congruence: SSS, SAS, ASA, and SAA. Are there shortcuts for similarity also?

 Suppose two triangles had one corresponding angle congruent. Would the triangles be similar?

  From the second step in the investigation you see there is no need to check AAA, ASA, or SAA similarity conjectures. Because of the Triangle Sum Conjecture and the Third Angle Conjecture AA Similarity Conjecture is all you need.

So SSS, AAA, ASA and SAA are shortcuts for triangle similarity.

So SSS, AAA, ASA and SAA, and SAS are shortcuts for triangle similarity.

So SSS, AA, and SAS are the only shortcuts you need to remember for triangle similarity.

   Discover shortcut methods for determining similar triangles Use proportions to find measures in similar figures Use problem solving skills

1. Find the missing values.

Show your work and Explain your reasoning 2. Write the similarity statement and give a proof of why the triangles are similar.

1. Find the missing values.

Show your work and Explain your reasoning 2. Write the similarity statement and give a proof of why the triangles are similar.