Similar Figures:

1
Similar Figures

• Polygons that have the same shape but may be
  different in size.

2
Similar Polygons

• 2 polygons are similar iff their corresponding
  angles are congruent and the measures of their
  corresponding sides are proportional.
• means is similar to

3
Order of Vertices

• ABCD EFGH means this
• Angle A is congruent to angle E
• Angle B is congruent to angle Fetc. and the
  corresponding sides would be
• AB/EF BC /FG CD/GH DA/HE.

4
Determine whether a pair of figures is similar by

• 1. proving each angle in triangle 1 is congruent
  to each angle in triangle 2.
• 2. Make sure that all corresponding sides are
  proportionalall ratios should equal the same
  number.

5
Scale factors

• The ratio that compares the two lengthsnote that
  the lengths must be in the same unit.
• Look at page 291 for example of scale factor.

6
Classwork

• With your partner, work out problems 70-72 on
  page 297.
• You have 5 minutes to do this.
• Next, lets work numbers 11-17 together
• Omit 16.

7
SSS similarity

• If the measures of the corresponding sides are
  proportional, then the triangles are similar.

8
SAS Similarity

• If the measures of 2 sides of a triangle are
  proportional to the measures of 2 corresponding
  sides of another triangle, and the included
  angles are congruent, then the triangles are
  similar.

9
Theorem 6.3

• Similarity of triangles is reflexive, symmetric,
  and transitive.
• Now lets work 10-20 even with a partner to make
  sure you can work homework tonight
• Homework is up on the website for chapter 6.

10
Homework

• 1. p 293-97 11-19 odd, 21,35,39-47odd,48,51,52
• 2. p301-306 5-17 odd, 18-22 all,32,35 18-22
  all,32,35