Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    16
    ReputationRep:
    Name:  1459288399915-1876165051.jpg
Views: 171
Size:  360.5 KB hi, I am a bit stuck on part b and c of this question. To solve this, apparently line Ad is perpendicular to l1 but how can that be as the angle in between isn't a right angle. I know that l1 and l2 are parallel and the other two lines are as well. Thanks.
    • Thread Starter
    Offline

    16
    ReputationRep:
    I need someone to explain why AD would be perpendicular to l1... Thanks in advance.
    Offline

    8
    ReputationRep:
    It's a parrallelogram so It can't be a right angle
    Offline

    22
    ReputationRep:
    (Original post by lytran)
    It's a parrallelogram so It can't be a right angle
    ...I, say what? A rectangle is a parallelogram... what are the angles in a rectangle?
    Offline

    8
    ReputationRep:
    (Original post by Zacken)
    ...I, say what? A rectangle is a parallelogram... what are the angles in a rectangle?
    But in that question , it didnt say a rectangle so i just assume that it's just this one
    Attached Images
     
    Offline

    22
    ReputationRep:
    (Original post by coconut64)
    Name:  1459288399915-1876165051.jpg
Views: 171
Size:  360.5 KB hi, I am a bit stuck on part b and c of this question. To solve this, apparently line Ad is perpendicular to l1 but how can that be as the angle in between isn't a right angle. I know that l1 and l2 are parallel and the other two lines are as well. Thanks.
    In answer to your question, AD is not perpendicular to \ell_1, either you are reading wrong or the markscheme is wrong. What I suspect is happening is that you are reading wrong and that the mark scheme is finding a line that passes through A and is perpendicular to \ell_1 but this does not imply that the line also passes through D.
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by Zacken)
    In answer to your question, AD is not perpendicular to \ell_1, either you are reading wrong or the markscheme is wrong. What I suspect is happening is that you are reading wrong and that the mark scheme is finding a line that passes through A and is perpendicular to \ell_1 but this does not imply that the line also passes through D.
    Yeah , sorry my mistake. I got confused that's why. So this is what I think is happening: find the perpendicular line to L1 going through A. Then find the point of intersection with L2. Then work out the distance between A and the point of intersection? Right?
    Offline

    22
    ReputationRep:
    (Original post by coconut64)
    Yeah , sorry my mistake. I got confused that's why. So this is what I think is happening: find the perpendicular line to L1 going through A. Then find the point of intersection with L2. Then work out the distance between A and the point of intersection? Right?
    Yes.
    • Thread Starter
    Offline

    16
    ReputationRep:
    (Original post by Zacken)
    Yes.
    Great. So this distance is the same as the length of AD/ bc ? Because for part c, they used length of AB and the distance found in the previous part of the question.
    Offline

    22
    ReputationRep:
    (Original post by coconut64)
    So this distance is the same as the length of AD/ bc ? Because for part c, they used length of AB and the distance found in the previous part of the question.
    Well... no - look up the definition of an area of a parallelogram, it's the side * perpendicular height. Not side * side. You can find the length AB and you've just found the perpendicular height, not AD.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.