## marcoduuuh 3 years ago In the diagram below, BD is parallel to XY. What is the value of x? Note: BD and XY have the little line over them but I have no idea how to put it. (Picture below.)

1. marcoduuuh

2. marcoduuuh

I'd say 55. Am I right? Or it's 125?

3. dpaInc

HINT: x and 125 are supplementary...

4. AriPotta

5. dpaInc

ur correct....

6. marcoduuuh

How do I know if they're supplementary?

7. AriPotta

because it's a straight line

8. AriPotta

they're a linear pair

9. Geometry_Hater

It would add up to equal 180

10. marcoduuuh

How do I know if I should put 55 or 125 because last time I did a problem like that and the answer was the same as 125.

11. AriPotta

it's 55

12. AriPotta

i did the math on that pic i posted

13. marcoduuuh

Does it have to do with the lines? For example this question:

14. Geometry_Hater

Its the lower angle (It looks smaller so it has to be 55)

15. marcoduuuh

^ The answer for that one was 67.

16. AriPotta

right, because those angles were alternate exterior angles

17. marcoduuuh

Supplementary lines: subtract from 180. Alternate exterior angles: the same as the other line. Am I right? If yes, how do I know the difference from both of the different lines?

18. AriPotta

19. AriPotta

that shows congruency

20. AriPotta

and any angles who are on a straight line add up to 180

21. AriPotta

because, it's a straight line and straight lines are 180 degrees

22. AriPotta

does that make sense?

23. marcoduuuh

I think so... Okay, let me see if I've got it. Okay, so for that one... That's a Alternate exterior angle?

24. AriPotta

those are corresponding angles

25. Geometry_Hater

X is corresponding

26. AriPotta

they are congruent too though

27. marcoduuuh

See... That's what I don't understand. How do you guys know they are congruent. Sorry. i'm stupid. :/

28. AriPotta

look at the pic i posted

29. AriPotta

it shows all angles that are congruent

30. Geometry_Hater

All lines are 180. So whenever we have an angles like that they will always equal 180 degrees together

31. marcoduuuh

Wait... I'm thinking haha.

32. marcoduuuh

Okay, so if they're congruent that means they have the same number right? 110 would be the answer for that one?

33. AriPotta

yea

34. Geometry_Hater

Thats right

35. marcoduuuh

Okay so for this one it isn't congruent am i right? so the answer would be 75?

36. AriPotta

those are congruent

37. AriPotta

they are also corresponding angles

38. Geometry_Hater

They are corresponding because they are in similar places

39. marcoduuuh

AHHHHHHHHHHHHHHHHHHH. I DON'T GET THIS.

40. AriPotta

:/ i'm not sure how to explain it

41. Geometry_Hater

Hmm hold on

42. Geometry_Hater

|dw:1349397323829:dw| 1 and 5 would be corresponding angles because they are in the same places

43. AriPotta

44. AriPotta

if you can read what i wrote lol.

45. marcoduuuh

I can! Wait... So that would mean every line is corresponding? Why do I sometimes have to put the same number that's on top and then other times i have to subtract from 180..

46. Geometry_Hater

Every line isnt corresponding......... For instance in my drawing 1 and 5 are corresponding but not 1 & 6

47. AriPotta

no, no. i mean those ANGLES are corresponding

48. AriPotta

the lines are parallel and cut by a tranversal which makes the angles i listed corresponding and congruent

49. marcoduuuh

Thank you so much guys!

50. AriPotta

no problem :) do you understand it better?

51. marcoduuuh

yep! I hope so!

52. AriPotta

good luck with your other questions!

53. marcoduuuh

Thank you so much! Seriously!