Question

Find the vertices of a triangle,the mid points of whosesidesare(3,1),(5,6),and(-3,2).

Answer 1

A(x1, y1).  B(x2, y2).  C(x3, y3).
Mid points D(3,1).  E(5,6).  F(-3 ,2).

x1 + x2 = 2 * 3 = 6         ... y1 + y2 = 2
x2 + x3 = 10 ...                  y2 + y3 = 12
x3 + x1 = -6 ...                   y3 + y1 = 4

Solve:  x3 = -1.  x1 = -5,   x2 = 11.
            y2 = 5.  y1 = -3.  y3 = 7.

Ans:  (-5,-3), (11, 5), (-1, 7).