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## anonymous one year ago Can I get some help with a few questions?

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1. zzr0ck3r

?

2. anonymous

One moment, need to screenshot!

3. anonymous

4. UnkleRhaukus

two angles are supplementary, iff they add to 180°

5. anonymous

Okay..

6. UnkleRhaukus

iff $$\angle FEA$$ is supplementary to $$\angle HGD$$ $\text m\angle FEA+\text m\angle HGD = 180°$

7. anonymous

Wait.. I don't understand...

8. UnkleRhaukus

consider the first option, does it agree?

9. anonymous

Yes?..

10. UnkleRhaukus

What is it that you don't understand?

11. anonymous

Just the overall question. It's weird. It's not option A or B is what I'm getting so far, right?

12. UnkleRhaukus

(check carefully now) Does: $\text m\angle FEA+\text m\angle HGD = 180°$ agree with option one?

13. anonymous

It.. it's not 180, I think..?

14. UnkleRhaukus

I suppose the first thing you have to realize is that any angle, can only have one supplement so iff ∠FEA is supplementary to ∠HGD then effectively A = C, B= D, E=G, F=H

15. UnkleRhaukus

there are only two angles to consider; the big one : ∠FEB = ∠HGD and the little angle : ∠FEA = ∠HGC

16. UnkleRhaukus

where any pair, of one big and one little angle, will always add to 180°,

17. anonymous

So A is not true, which makes it the right answer?

18. UnkleRhaukus

but why is A not true?

19. anonymous

Because the angles are too big, right?

20. UnkleRhaukus

yeah, big angle + big angle ≠ 180°

21. anonymous

Okay, I kinda get it...

22. anonymous

What about this problem?

23. UnkleRhaukus

(unless all the angles were exactly 90°, which doesn't fit the diagram )

24. UnkleRhaukus

[if i remember correctly] alternate angles are equal, corresponding angles are equal, vertically opposite angles are equal , & co-interior angles are supplementary.

25. UnkleRhaukus

can you find the angles in the first option on the diagram?

26. UnkleRhaukus

|dw:1434794031396:dw|

27. anonymous

In the first one, they look equal to me.. unless I am not understanding this properly.

28. UnkleRhaukus

if they look equal (congruent), are they alternate angles? corresponding angles? vertically opposite angles ?

29. anonymous

Alternate, I think..

30. UnkleRhaukus

u can't see any angles alternate to angle EIA

31. anonymous

So it's the first option, yes?

32. UnkleRhaukus

|dw:1434794616346:dw|

33. UnkleRhaukus

|dw:1434794679515:dw|

34. UnkleRhaukus

35. anonymous

Oh, so they're opposite angles?.. so they are congruent.

36. UnkleRhaukus

Yes!

37. anonymous

Then there's this... I was always bad at these in class.

38. UnkleRhaukus

what is the difference between line 3, and line 4?

39. anonymous

They're adding segments together and asking if they're congruent.

40. UnkleRhaukus

3. AB + BC + CD = CD + DE + EF 4. AB + BC = DE + EF What has happened ?

41. anonymous

They're.. substituting I think?

42. UnkleRhaukus

what has been substituted for what?

43. anonymous

The concurrency, I think.

44. anonymous

*congruent

45. UnkleRhaukus

nope

46. UnkleRhaukus

3. AB + BC + CD = CD + DE + EF 4. AB + BC = DE + EF how are theses lines different ?

47. anonymous

Uh.. I have no legitimate clue.

48. UnkleRhaukus

read line 3. and then read line 4.

49. anonymous

It removed two of the segments, I see that much.. :/

50. anonymous

@TillLindemann no CD

51. UnkleRhaukus

yeas, CD has been taken away from both sides of the equation

52. anonymous

Okay.. so it's asking if they're still congruent without them, no?

53. anonymous

So would it not be D?..

54. UnkleRhaukus

The question is , what reason justifies us being able to take away some term that appears on both sides of the equation

55. anonymous

So D, yes? I'm so confused.

56. UnkleRhaukus

another word for take-away or minusing, is subtraction

57. anonymous

Wait. So.. It's C?

58. UnkleRhaukus

does that makes sense now?

59. anonymous

Yes, because they removed one of the segments, it makes it the Subtraction property, right?

60. anonymous

This is one of those ones where you have to do a bunch of weird nitpicking to get the correct answer...

61. UnkleRhaukus

Yes, the subtraction property of equality states that: if some expression is equal to some other expression, and both expressions have +some term, you can take away the +some term form both sides and the resulting expressions will still remain equal to one another A + c = c+ B (taking away c) A = B

62. anonymous

63. anonymous

Not sure, but I think it's linear and angle BED...

64. anonymous

Er, not angle.. but.. you get what I'm trying to say.

65. anonymous

66. UnkleRhaukus

what is the linear angle theorem?

67. anonymous

|dw:1434796331473:dw| This right?

68. UnkleRhaukus

that might be the linear angle theorem, but i don't see how it relates to this question

69. UnkleRhaukus

you got $$\angle AEC \cong \angle BED$$ (by the vertical angle theorem) right

70. UnkleRhaukus

the linear angle theorem is not about congruence (equality), it is a about supplementary angles

71. anonymous

Okay, but?...

72. UnkleRhaukus

compare the two lines of this question

73. anonymous

Is it vertical?..

74. UnkleRhaukus

yer

75. anonymous

And still angle BED, right?

76. UnkleRhaukus

yep they are vertically opposite angles in each case

77. anonymous

This one is really long as well.

78. UnkleRhaukus

what do you think

79. anonymous

Well, I've had this question multiple times before and I always get it wrong...

80. anonymous

81. anonymous

82. anonymous

83. UnkleRhaukus

i'm not going to tell you what the answer is

84. anonymous

I know that, but I haven't a single clue on how to find it..

85. UnkleRhaukus

Which parts of the closed passage do you not understand exactly?

86. anonymous

Well, this whole section really.

87. UnkleRhaukus

first line says some lines are parallel, some angles are equal. prove some other angle are supplementry

88. anonymous

Yes, I think the first answer to the big question is transitive..

89. UnkleRhaukus

i think that is right, what about the next one

90. anonymous

Vertical maybe...

91. UnkleRhaukus

vertical angles are congrunent (not supplementary )

92. anonymous

It's not linear, right?.. or is it?

93. UnkleRhaukus

Which do you think ?

94. UnkleRhaukus

|dw:1434798665055:dw|

95. anonymous

I think it's linear but I have no clue.. could be the congruent supplements one though.

96. UnkleRhaukus

the congruent supplements theorem involves three angles you have plenty of clues

97. anonymous

So then it is linear, no?

98. UnkleRhaukus

why not, eh?

99. anonymous

And I think the last one is substitution, because it's assuming, and substituting numbers into the whole thing.

100. UnkleRhaukus

Yep substitution is right

101. anonymous

102. anonymous

I think it's the first option...

103. UnkleRhaukus

that doesn't prove the what you are trying to prove

104. UnkleRhaukus

the last line of the proof should say something about what you are trying to prove

105. anonymous

The congruent supplement one, yeah.. I think that's the right answer.

106. UnkleRhaukus

In this question you are trying to prove that $$\angle 3\cong \angle 6$$, ... you have $$\angle 3\cong \angle 7$$, ... you need something$$\cong\angle 6$$, ...

107. anonymous

Now I feel like it's more option D...

108. anonymous

B?...

109. UnkleRhaukus

stop guessing

110. anonymous

Well I don't understand.

111. UnkleRhaukus

$\angle 3\cong \cdots\cong\angle6, ...$

112. anonymous

That doesn't help me.

113. anonymous

Because there is no option with 3 and 6 in it at the same time.

114. UnkleRhaukus

you have $\angle 3\cong \angle 7, ...$ you need $\angle 7\cong\angle6, ...$

115. anonymous

So it'd D.

116. UnkleRhaukus

Um, yes it is.

117. anonymous

Thank you. That's all I needed for now. Thanks so much for helping.

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