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# Triangle

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1. Given the three points A (3,4,0) , B (8,0,6) , C (0,5,12) in space . find
1)Area of the triangle ABC
2)the length of the three medians of this triangle
3)The measure of the angle ABC
4)Equation of the plane ABC
2. what have you done so far?
3. At least try it before coming on tsr with your homework questions... Why should we do it for you?
4. "Sigh" this is not a homework
5. I found 4) and 1) i need just a little hint for 2) and 3)
6. again, what have you done so far?

i have no idea what 2) is asking.
hint for q3 = cosine rule
7. For 1)
8. (Original post by MAA_96)
2)the length of the three medians of this triangle
Start by finding the coordinates of the centroid...

You should know what to do next.

If not:

Spoiler:
Show

Call the centroid .

Median from

Median from

Median from
9. (Original post by z0tx)
Start by finding the coordinates of the centroid...
Do i have to use midpoint and use the distance formula or...to find that ?
10. (Original post by MAA_96)
Do i have to use midpoint and use the distance formula or...to find that ?
Nope, midpoints would be a waste of time.

The coordinates of the centroid are:

Keep that in mind for future problems involving triangles!

Also, in case you don't know: the median is 3/2 of the distance between the vertex in question and the centroid.
11. I should that yes, you could find the three midpoints and calculate the three distances, but why do something thrice when you can do it once?
12. Nice,but why did you choose centroid here?
13. (Original post by MAA_96)
Nice,but why did you choose centroid here?
I just told you. Finding the centroid (i.e. a single point) is quicker than finding all the midpoints (i.e. three points).
14. Alright,thank you.

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