The height of a triangle, given 2 vectors and the area

[heidihiiiiiii]

Homework Statement

Triangle ABC formed by two vectors a = ( 2, 10, 25 ) and b = ( 5, 4, -2 ) attached at a point A.
The area of the triangle is (81 root 5) / 2
And I need to find the length of the height AM (AM perpendicular to BC and the point M belongs to the line BC).
Don't know where to start!

Homework Equations

Area = 0.5 *h *b

 

[radou]

Hint: find the magnitude of the difference of the two given vectors first.

 

[Dick]

Don't open two posts on the same problem, ok? https://www.physicsforums.com/showthread.php?t=397993