section 8.3 similar polygons. similar figures two figures that have the same shape are similar –...
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Section 8.3 Similar Polygons
Similar Figures
• Two figures that have the same shape are similar–Not necessarily the same size!–Enlarging and shrinking
Real life example of Similarity
Similar Polygons• Two polygons are similar if:–corresponding angles have the same
measure–corresponding sides are in proportion–Symbolic notation for similarity: ~
Congruent vs. Similar
Congruence Similarity
Similarities
Figures are the exact same size and shape
Corresponding sides are equal
Corresponding angles are equal
Figures have the same shape but not necessarily the same size.
Corresponding sides are in proportion
Corresponding angles are equal
Both have corresponding angles that are equal.Same shape of the object
Both have a symbolic notation
Example of Similar Polygons
ABCD ~ EFGH
________ = _________ =__________=_________
Similarity Statement
Statement of Proportionality
How to determine similarity:
• Are corresponding angles equal?• Are corresponding sides in
proportion?–Are the ratios the same?
Are they similar?
Are they similar?
Scale Factor• Ratio of the lengths of two
corresponding sides of similar figures.• Corresponding sides change by
the same scale factor. –What does this mean?
It means that all the sides of the small figure are multiplied by the same number to obtain the lengths of the corresponding sides of the large figure.
Find the scale factor.
Find the scale factor.
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