Geometry 7.1 Notes (With an intro to 7.2.)
Ratio
January 31, 2017
Expression that
compares two quantities
by division.
Examples:
Proportion
An equation involving ratios.
"Proportional"
and
Must be true if the
proportion is true.
The ratios
form a
True Proportion.
Geometry 7.1 Notes (With an intro to 7.2.)
Examples:
January 31, 2017
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
"Extended Ratios"
Say the ratio of 3 quantities is a:b:c
That means....
first two quantities compare by: a:b
last two quantities compare by: b:c
and
first and last quantities compare by a:c
Geometry 7.1 Notes (With an intro to 7.2.)
Example:
January 31, 2017
Geometry 7.1 Notes (With an intro to 7.2.)
Example:
January 31, 2017
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Thoughts about Proportions from the BOOK:
"If a proportion is 'TRUE' then the
product of the extremes is always
equal to the product of the means."
ad = bc
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
All of these proportions are
EQUIVALENT.
(Notice what happens when you cross multiply.)
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Similar figures:
"Casual" Definition:
Same Shape, Different Size
"Formal" Definition:
All corresponding angles are
congruent.
All Corresponding Sides are
Proportional.
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Similar?
maybe...
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Similar?
maybe...
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Similar?
NO!!
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Similar?
YES,
Symbol for
"Is Similar To"
Pentagon ABCDE
~
Pentagon TSQRU
Geometry 7.1 Notes (With an intro to 7.2.)
January 31, 2017
Finish Exams
7-1: 10 - 29, 31 - 37, 54 - 59
7-2: 9 - 29, 31 - 36, 39, 40 - 45