Geometry Chapter 7
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A ratio is a comparison of two quantities
Ratios can be written:
a to b, a:b or a/b
the fractional form is the most common and
easiest to use mathematically
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Two figures that have the same shape but not
necessarily the same size are similar.
Two polygons are similar if BOTH:
◦ Corresponding angles are congruent AND
◦ Corresponding sides are proportional
◦ The ratio of the lengths of corresponding sides is
the similarity ratio.
Are the polygons similar? Explain. If they are similar, what is the
similarity ratio?
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On a blank sheet of paper, draw a line
segment.
Glue the two angles you are given to the end
points of the segment and finish the triangle
by extending the remaining sides.
Measure the sides of your triangle to the
nearest millimeter.
Compare your triangles to your table partners
and determine if they are similar.
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Are your triangles similar?
Complete this conjecture:
If two angle of one triangle are congruent to
two angles of another triangle, then the
triangles are ____________________
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Explain why the triangles must be similar.
Homework: page 385 (1-19) all
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Homework: page 394 (9-21) all
Chapter 7 test next week
Tuesday/Wednesday
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warm up