Download week 3-4 unit 3 and 4 conclusion week

15 minutes
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How do you know a triangle is a right triangle
and what is rigid motion?
Rigid motion – when you reflect, rotate,
translate a pre image the image will have the
same size and shape! Rigid – it stays the
same…strict, won’t budge
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http://youtu.be/bbYuCj_eM_w
http://www.ck12.org/section/UsingCongruent-Triangles
Unit 3
Chapters 4.2, 4.3, 4.6
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The angle is the right angle and the sides are
the hypotenuse and one of the legs
Students cannot use the hypotenuse leg (HL)
theorem if they know ONLY that the legs are
congruent. In this case, they can still prove
that the triangles are congruent by SAS
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The measure of a (n) ___________ of a
triangle is equal to the sum of the measures
of its two remote (far side) interior angles.
The measures of the three angles of a
triangle are given. Find the value of x and
tell me the angle degrees. (complete both
2a and 2b)
◦ X, 2x, 3x
◦ X + 10, x – 20, x + 25
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Explain how you find the missing angle
measure in a triangle? Be specific
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What is the theorem to find the interior
angles of a polygon? Describe how it is used
with your favorite type of polygon.
What theorem will allow you to prove that
the last pair of angles is congruent?
How can you find distances on a coordinate
plane without measuring? Describe &
provide an example
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Problems in book 4.2, 4.3, and 4.6
work on scale model design (due Wednesday)
create flip books to understand 5 types of
triangle congruency
4th block needs to finish congruency posters
or quadrilaterals and present
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6-1
3-5
Scale models
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Do now:
define / describe an isosceles & equilateral
triangle
and
Turn to page 357 and attempt #30
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What do all these people have in common?
What do they each need to build first? (design
first)
http://www.virtualnerd.com/geometry/simila
rity/ratios-proportions/scale-model-scalefactor
3-5-13
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Related to text
3.5, 4.1, 4.2, 4.3, 4.5, 4.6, 5.1, 5.4
(congruence)
Quadrilaterals 6.1, 6.5
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Actual measurements of appropriate
object/building
5 points
Scale factor / ratio (shown in key) 3 points
Unit of measurements (inch/feet)
3points
Dilated correctly to see similarity
5 points
Color
3 points
Quadrilaterals/triangles used
3 points
Described the transformation occurring in
scale model
3 points
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Need to consider the location of angles and
sides of triangle
Proportions & ratios for comparing
corresponding sides
You may have to consider the definitions and
concepts of the different types of angles from
unit 1
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1) scale model due Friday (unless you are
building a 3-D image and then due Tuesday
3/12)
2) congruence problems & quadrilateral
problems (due Friday on loose-leaf paper, not
in notebook)
Pg. 230 lesson check (SSS) all
Pg. 238 lesson check 1 – 4 only (ASA)
Pg. 263 problems 15 and 25
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Two angles of a triangle are x and 10 + x,
what is the third angle? What is x?
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Activating – all the places that geometry is
used
http://youtu.be/MvDrn384JYA
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is a triangle a quadrilateral?
What is a quadrilateral? (how do you define?)
http://youtu.be/3foPrQgZHWE
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Why do we need scale factors?
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Go over triangle congruence problems and
mid chapter quiz
Discuss SSS, SAS, AA, HL, and AAS
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1. use a ruler to draw & label any type of
triangle on tracing paper (label ABC)
2. use a ruler to carefully measure segments
AB and AC. Use a protractor to measure the
angle between them, angle A
3. Write the measurements on an index card
& swap cards with a classmate. Draw a new
triangle using ONLY your classmate’s
measurements
4. compare new triangle to your original
triangle
 5. try to make your classmates' triangle fit
exactly on top of your new triangle
Questions:
1. Is your new triangle congruent to your
original triangle?
2. Conjecture: what seems to be true about 2
triangles when they have 2 congruent sides
and a congruent angle between them?
3. Conjecture: At least how many triangle
measurements must you know in order to
guarantee that all triangles built with those
measurements will be congruent?
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Do now:
Use the distance formula to prove triangles
ABC and DEF are congruent. Justify your
answer
A (1,4) B (5,5) C(2,2)
D(- 5, 1), E (-1, 0), F (-4, 3)
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Activating – song about congruence
http://www.songsforteaching.com/math/geo
metry/proportionscongruenceofshapes.htm
Here are the lyrics, can you think of song to
act out
Pg. 242 AAA, SSA
1. Form a triangle with segment AB and AC.
2. Then construct BC segment
3. Construct a line parallel to BC that
intersects AB and AC at points D and E to
form triangle ADE
4. Are the two triangles congruent? Can the
two triangles be congruent?
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Scale model due today
Problems: pg. 230, 238, 263
4-6 pg. 243 mid chapter quiz
And
Review Worksheet with problems 1 – 8 (DO
NOT WRITE ON WORKSHEETS)
SHOW WORK IN YOUR NOTEBOOK!!
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Create a 6 word phrase/sentence describing
triangles, congruence, and/or quadrilaterals
Stipulations: you cannot use the following
words – today I learned, I enjoyed today, I
now know about
What you could start with: Geometry deals
with: OR Congruence is important because
Write legible & big enough so we can see if I
post!
1.
2.
3.
4.
5.
Cut straws into 3 pieces (4 inch, 5 inch, 6
inch)
Thread string thru 3 pieces of straw
Pieces of straw can be in any order
Bring the 2 ends of the string together and
tie to hold triangle in place
Compare with your classmate
1.
2.
3.
4.
Is your triangle congruent with your
classmates’ triangle?
Make a conjecture – what seems to be true
about 2 triangles in which 3 sides of one are
congruent to 3 sides of another?
As a class, choose 3 different lengths and
repeat steps 1,2 ,3
Are all the triangles congruent? Does this
support your conjecture from question 2