KrystaRenee Complete the two-column proof. Given: ∠2 and ∠5 are supplementary Prove: L II M one year ago one year ago

1. KrystaRenee

2. KrystaRenee

Statements Reasons 1. _____________ 1. _____________ 2. ∠ 3 is congruent to ∠ 2 2. _____________ 3. ∠ 3 and ∠ 5 are supplementary 3. _____________ 4. _____________ 4. _____________

3. AriPotta

what's the first statement in all proofs

4. zonazoo

5. zonazoo

An echo...

6. AriPotta

i'll leave you to it lol

7. zonazoo

you got it... you answered first.

8. AriPotta

nah, it's coo. i got algebra work to do

9. KrystaRenee

I have no idea what I proof even is.

10. KrystaRenee

*a

11. AriPotta

how...what...

12. KrystaRenee

Like I've got taught, just never got the hang of it.

13. AriPotta

this is a two-column proof. it's a proof with two columns. you list the statements in one column and the justifications for your statements in the other

14. KrystaRenee

Yeah, I get that part lol.

15. AriPotta

you use theorems and postulates for your justifications

16. AriPotta

the first statement in any proof (except indirect proofs) is the given information

17. AriPotta

so...what goes in our first blank?

18. AriPotta

@KrystaRenee ? :/

19. KrystaRenee

I really don't know.. Like how am I supposed to figure out what to put in the spaces?

20. AriPotta

well, i just said that the first statement is the given information. what's given to us? (look at the question you posted)

21. KrystaRenee

That's what I thought. So that <2 and <5 are supplementary. But what do they mean by give a reason?

22. AriPotta

the reason would be "given"

23. KrystaRenee

OHH, I feel like a dumb retricelol I got what you mean by that.

24. KrystaRenee

I wrote a s s lol not retrice..

25. AriPotta

lol i know. they have filter words on here

26. AriPotta

so the next statement is "angle 3 is congruent to angle 2" what can be our justification for that?

27. KrystaRenee

I guess that when a segment is bisected, the two resulting segments are congruent.

28. AriPotta

they never stated anything regarding bisectors. and we're talking about angles, not segments :/

29. KrystaRenee

Ohhh. Sorry got mixed up.

30. AriPotta

what kind of angles are 2 and 3?

31. KrystaRenee

Congruent.

32. KrystaRenee

No that's wrong I think. I'm getting confused.

33. AriPotta

well, obviously they're congruent :/ but what i mean is like...are they vertical angles, adjacent angles, same-side interior angles, etc.

34. AriPotta

what kind of angles guarantee that angles 2 and 3 are congruent

35. KrystaRenee

Vertical angles I believe.

36. AriPotta

yes! so we can say that reason two is "vertical angles theorem"

37. AriPotta

so far, we have: 2 + 5 = 180, and 2 = 3

38. KrystaRenee

Ok. Now we're getting some where lol. Sorry, I'm a slow learner. So the reason for 3 would be that it's using the corresponding angles theorm?

39. AriPotta

no it's not

40. AriPotta

because we haven't proved that L and M are parallel

41. KrystaRenee

I thought that was for number 4?

42. AriPotta

yes, but we can't just say "corresponding angles postulate" as a reason in a proof that is trying to prove that the lines are parallel...

43. AriPotta

we have to prove that the two angles are supplementary first.

44. KrystaRenee

Oh.

45. AriPotta

again, what we have so far is:2 + 5 = 180; 2 = 3. now we're saying that 3 + 5 = 180...

46. AriPotta

our reason for saying that 3 + 5 = 180 is...?

47. AriPotta

substitution.

48. AriPotta

because 2 = 3, we can replace the 2 with 3 in the equation 2 + 5 = 180, giving us 3 + 5 = 180. does this make sense?

49. KrystaRenee

Yeah, it's all just confusing to me..

50. AriPotta

i don't know how to make it any less confusing :/ can you tell me what exactly you don't get?

51. KrystaRenee

All of it is. I'm just a slow learner.. But you're helping the best you can. So I'll try to bear with you here lol.

52. AriPotta

:) ok, just tell me when you want an explanation and i'll explain

53. KrystaRenee

Thank you. :)

54. AriPotta

what's our last statement?

55. KrystaRenee

Something to do with L II M ?

56. AriPotta

yes, our last statement is always the "prove:"

57. AriPotta

so it will be "L II M"

58. KrystaRenee

So in the space I just put L II M ?

59. AriPotta

yes, that's our last statement

60. AriPotta

now we need a justification

61. AriPotta

what makes L ll M?

62. AriPotta

any ideas? :l

63. KrystaRenee

Am I supposed to name a theorem?

64. AriPotta

yes lol. well, it's actually the converse of a postulate

65. AriPotta

what kind of angles are 3 and 5?

66. KrystaRenee

Supplementary ?

67. AriPotta

yes, they're supplementary, but what i mean is like, are they corresponding angles, alternate interior angles, same-side interior angles, etc.

68. KrystaRenee

Ohh, corresponding angles.

69. AriPotta

no :/

70. KrystaRenee

Damn it. Same side interior?

71. AriPotta

yes :)

72. KrystaRenee

Finally lol!

73. AriPotta

so our last justification is "converse of the same-side interior angles postulate"

74. AriPotta

did all this make sense to you?

75. AriPotta

would you be able to do a similar proof by yourself?

76. KrystaRenee

Awesome. Thanks for your help. You're a life savor! It some what did. I'm gonna need a lot more practice though, that's for sure.

77. AriPotta

:) well, good luck to ya