MGMAT co-ordinate geometry

[abhi75]

Line l is defined by the equation y – 5x = 4 and line w is defined by the equation 10y + 2x + 20 = 0. If line k does not intersect line l, what is the degree measure of the angle formed by line k and line w?

0
30
60
90
It cannot be determined from the information given.

This is another problem where I dont get the solution provided by MGMAT. The answer is not e.

Can someone please explain it.

Answer is D.

[camitava]

Line l is defined by the equation y – 5x = 4 and line w is defined by the equation 10y + 2x + 20 = 0. If line k does not intersect line l, what is the degree measure of the angle formed by line k and line w?

0
30
60
90
It cannot be determined from the information given.

This is another problem where I dont get the solution provided by MGMAT. The answer is not e.

Can someone please explain it.

Answer is D.

Abhi, refer the point - line k and line l are not intersecting at all. So these lines have to be parallel. If so slope of k = 5 ->Got it Abhi?
Again slope of line w = -2/10 = -1/5
Now slope of k * slope of w = -1
So they are perpendicular to each other.
So the angle is 90. So IMO D. Got my response, Abhi?

[Kekela]

camitiva,

can you explain this:

Now slope of k * slope of w = -1
So they are perpendicular to each other.

[camitava]

camitiva,

can you explain this:

Now slope of k * slope of w = -1
So they are perpendicular to each other.

Kekela, I would like to say - please go thru the tutorials provided by GMATPrep s/w or do some google search. The point I mentioned earlier, is a basic co-ordinate geometry principle.

[Kekela]

ok, thanks!

[rbhavikatti]

Line l is defined by the equation y – 5x = 4 and line w is defined by the equation 10y + 2x + 20 = 0. If line k does not intersect line l, what is the degree measure of the angle formed by line k and line w?

0
30
60
90
It cannot be determined from the information given.

This is another problem where I dont get the solution provided by MGMAT. The answer is not e.

Can someone please explain it.

Answer is D.

Abhi, refer the point - line k and line l are not intersecting at all. So these lines have to be parallel. If so slope of k = 5 ->Got it Abhi?
Again slope of line w = -2/10 = -1/5
Now slope of k * slope of w = -1
So they are perpendicular to each other.
So the angle is 90. So IMO D. Got my response, Abhi?

But the question says, two lines never intersect, then where is this measure of angle betwwen them come from????

[xilef]

rbhavikatti,
it says 'line k does not intersect line l...' and asks for the measurement of the angle formed by line K and line W. Please read the question carefully before posting.

[resilient]

I can see your point for the confusion. Can you notice that the slopes of l and w are negative reciprocals. TO help ease all confusion, make sure to map out or draw out as much as possible. THis will give you more clarity!