Download Chapter 7 Similarity

Chapter 7 Similarity
Big idea: showing two triangles are
similar
• 15 minutes of D.E.A.R
Agenda
1. DO NOW: center point of rotation is P (1, 1),
the shape to rotate 40 degrees has the
ordered pairs A (5, 1), B (8, 1), and C (3, 3)
2. Launch: grab bag (are the objects similar)
3. Chapter 7 (`get a book)
4. Quiz
5. Practice
6. Wrap up
7-1
• Proportions – statement equating 2 ratios
Extreme 3 = 5 mean
Mean
5
x extreme
Pg. 456
The cross products of proportions are equal
Product of means equals product of extremes
Properties of Proportions pg. 458
Proportions: We Do
• Pg. 459 10, 12
• Pg. 460 18, 20
• Pg. 460 28, 30
• You do: 7 – 1 worksheet (1, 5, 7, 8, 10, 12, 14)
Do Now
Solve the following proportions:
1)
x/4 = 77/ 281
2)
8 / (2y – 3) = 6 / (y + 4)
launch
• About congruence and similarity and triangle
thms.
Proving similar triangles
• 2 triangles are similar if and only if
corresponding angles are congruent &
corresponding sides are proportional
• Pg. 461 #50
Theorems
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7 -1 SAS pg. 475
7-2 SSS
Examples pg. 476
Proof pg. 477
Algebra review
• Solving quadratic equations pg. 462
Do now
• Pg. 480 #8 & 9 in book
• Follow directions, use sentences to prove
• When everyone here we are going to media
center, you don’t need to bring anything,
except pen/pencil
AA similarity postulate
• Angle angle postulate
• If two angles of one triangle are congruent to
two angles of another triangle then the
triangles are similar
• Pg. 474
10-10-12
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15 minutes of D.E.A.R
Warm up on board
Bring test up when done
When done get a book, turn to page 515 and
read about pythagorean thm
7- 2 similar polygons
• Similar figures have same shape, not
necessarily same size ( ~ similar)
• Similar polygons pg. 463
• Scale factor – ratio of corresponding linear
measurements of two similar figures
We do
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Scale drawing and scale pg. 467
Pg. 469 #12, 16
Pg. 470 #22, 24
Pg. 470 #32
Pg. 471 #50, 52, 54
We do
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Pg. 480 #8, 10
Pg. 481 #16
You do: pg. 481 #20, pg. 482 #26,
You do: pg. 482 #38, #40
Wrap up
• Solve the following proportion
5=
X+2
3
x+1
Describe corresponding angles of parallel lines
and how do they compare with corresponding
angles in polygons
homework
• Remember, your area/scale factor drawing is
due Friday
• Test Tuesday 10/9/12