A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Triangle ABC has been rotated 90° to create triangle DEF. Using the image below, prove that perpendicular lines have opposite and reciprocal slopes. You must show all of your work to receive credit.

  • This Question is Open
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    1 Attachment
  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    please help, i have 3 weeks untill i go to boot camp and i have to finish school.

  3. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can you "read off" the (x,y) coords for points B and C ?

  4. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    B (5, 4) C (1, 1)

  5. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok on C for B, you want the "sideways" number (the x) first you did it backwards.

  6. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    my bad, i havent always been real sharp in math, physics and space science are my thing

  7. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I assume you figured out we have B( 4,5), C(1,1) now find the slope. slope is change in y divided by change in x can you do that ?

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  9. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    is the slope 1?

  10. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    change in "y" means subtract the y values , for example y value of pt B - y value of pt C what do you get ?

  11. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so i would subtract 5 from 4? or the other way around

  12. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    neither. the y value of point B (4,5) is the 2nd number in that pair then you find the y value of point C (1,1)

  13. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm lost

  14. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok, try this put your finger on point C in the graph count straight up until you are at the same height as point B how many steps up is that ?

  15. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    4

  16. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    now count to the right until you get to point B if you move right, count that as a positive number how many steps do you move sideways?

  17. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    3

  18. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    you just found change in y (up 4) and change in x (3 to the right) or rise/run (is how some people call it) in other words, the slope is 4/3 (that is change in y divided by change in x) now we have to find the slope of the other line.

  19. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can you find the change in y from point F to pt E ?

  20. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    4/4

  21. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    no. just put your finger on pt F, and count up until you are at the same height as point E how many steps up ?

  22. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sorry 3/4

  23. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    almost. if you start at F and go up 3 steps that is +3 for change in y but when you move sideways you go left 4 steps. write that as -4 (if you went in the other direction, to the right, that would be plus) what is the slope?

  24. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    3/-4

  25. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes, or just \[ - \frac{3}{4} \] (it means the same thing) lines are perpendicular if when you multiply their slopes, you get -1 what do you get when you multiply \[ \frac{4}{3} \cdot - \frac{3}{4} \]?

  26. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i got 1/1 which is just 1

  27. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    my bad forgot negative

  28. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I would write it this way: multiply top times top and bottom times bottom \[ \frac{4}{3} \cdot - \frac{3}{4}= - \frac{12}{12} = -1\]

  29. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    they want you to show your work, so they may want to see how to calculate the slope (rather than count steps on the graph)

  30. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok

  31. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    F (-1,1) E(-5,4) change in y is 1 - 4 = -3 change in x is -1 - -5= -1+5 = 4 change in y divided by change in x is -3/4 = - 3/4

  32. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    okay its kinda starting to make sense

  33. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    is that the final product

  34. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    you can have your medal back when you come back...

  35. phi
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    they want you to **prove that perpendicular lines have opposite and reciprocal slopes*** (though I would say "negative reciprocal") to do that , and show your work find the slope of each line. I showed you how to do it for the 2nd line try to do the same thing for the C E line (you know the correct answer) then say 4/3 and -3/4 are opposite reciprocal slopes, because when you multiply them, you get -1

  36. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ten 4

  37. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.