1. Assignment:
1­­>Set 40 (all) ­ Due Tomorrow (12/13)
2­­>Test #6 signed for extra credit??
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2. Lesson 40:
*Take your triangle and "rip off" each angle:
Then...line up each of the "angles" and tell me what you find!
SO....the sum of the measures of the angles of a triangle:
180 degrees
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3. Angle Pairs:
2 1
3 4
*Angles 1 and 2 are adjacent angles ­ they share a common side
(So are 2 and 3; 3 and 4; 1 and 4)
*Angles 1 and 2 are also supplementary ­ they total 180 degrees
(So are 2 and 3; 3 and 4; 1 and 4)
*Angles 1 and 3 are vertical angles ­ they are a pair of nonadjacent angles that are
formed by intersecting lines
(Angles 2 and 4 are too!)
***Complementary angles ­ are 2 angles whose sum is 90 degrees!
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4. Examples (Lesson 40):
A) If the sides of a "regular" triangle are equal in length and the
angles are equal in measure, then what is the measure of each angle?
60 degrees
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5. Use the figure below to answer the following questions.
D A
70
C B
B) What is the measure of <ACB and why?
C) What is the measure of <CAB and why?
D) Are angles ACD and CAB vertical angles? Why or why not?
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6. E) Find the measures of <x, <y, and <z in this figure.
80
y
40 x
z
× =
y =
z =
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