coordinate geometry

rattan123 wrote:The mid points of a triangle are (x1,y1), (x2,y2), (x3,y3).find the vertices of the triangle?

p + r = 2x1...Equation 1
r + t = 2x2...Equation 2
p + t = 2x3...Equation 3
q + s = 2y1...Equation 4
s + u = 2y2...Equation 5
q + u = 2y3...Equation 6

Eqn 1 - Eqn 2 gives
p - t = 2(x1 - x2), now adding this equation to equation 3,
2p = 2x3 + 2(x1 - x2)
p = x3 + x1 - x2
x3 + (x1 - x2) - t = 2(x1 - x2)
t = x3 - x1 + x2

Similarly we can find the other coordinates. Hope that helps.

rattan123 wrote:thnx...this came as a question...this means i have done it correctly..

You are welcome!