Slide 1

Slide 2 DEFINING SIMILARITY ~ADAPTED FROM WALCH EDUCATION Slide 3 KEY CONCEPTS If two triangles are congruent, they are also similar. Similar triangles have the same shape, but may be different in size. If two triangles are similar, then their corresponding angles are congruent and the measures of their corresponding sides are proportional (have a constant ratio). Slide 4 When a triangle is transformed by a similarity transformation (a rigid motion [reflection, translation, or rotation] followed by a dilation), the result is a triangle with a different position and size, but the same shape Slide 5 WHAT ELSE? The ratio of corresponding sides is known as the ratio of similitude. The scale factor of the dilation is equal to the ratio of similitude. Similar triangles with a scale factor of 1 are congruent triangles. Slide 6 THE SYMBOL FOR SIMILARITY ( ~ ) IS USED TO SHOW THAT FIGURES ARE SIMILAR. Slide 7 Use the definition of similarity in terms of similarity transformations to determine whether the two figures are similar. Explain your answer. Practice # 1 Slide 8 DETERMINE WHETHER A DILATION HAS TAKEN PLACE BY CALCULATING THE SCALE FACTOR Find the length of each side using the distance formula Or Pythagorean Theorem Work through this example: find the length of each side, then set up your proportions. The ratio of similitude is 2. Slide 9 THANKS FOR WATCHING!!! ~MS. DAMBREVILLE