3-unit tomorrow, dividing by ration question (1 Viewer)

[S1M0]

A triangle is formed with vertices A(5,6), B(0,-4) and C (-3,3). Find the point of intersection of its medians

I NEED working working out, as in the steps as to how to do this. I've tried this, i know how to do it, but the answer always turns out wrong.

Please help, and please help soon.

 

[bos1234]

what does median mean?

 

[S1M0]

middle point of the lines.

 

[vulgarfraction]

The centroid's given by OG = {OA + OB + OC}/3, where all the thingies are vectors, but somehow I get the idea they don't want you to use vectors.....

That's the solution. Don't know about method. =P

 

[S1M0]

I need it solved using the division of 2 lines by ratio forumula.

Here's how its done:

1. Find the median points of each line
2. Join up the opposite point to the median point
3. Find the gradient of those lines
4. Use simultaenous equations to find (x, y)

Answers don't turn out at all right. So i need some help.

And my 3-unit test is on tomorrow!!!!

*PANIC!* :burn::burn::burn::burn:

 

[andykillz]

sorry if this is too late for your exam but if you draw up the triangle you will find that you don't need to find all the medians. Rather you need to find 2 medians and join up a to M(c,b) and b to M(a,c) ill post a diagram if it helps.

Edit: http://i25.photobucket.com/albums/c54/andykillz/problem.jpg

 

[vulgarfraction]

Are you allowed to use the fact that the centroid trisects each median, then?

If you have unlimited time you can always do it how they want you to:

-find midpoints
-join medians (you might have to find all three because they probably won't even let you use the fact that the medians are concurrent becaues they're pedantic and stupid like that)
-find equations of medians
-solve simultaneously

real fun.

And you don't have unlimited time anyway....