Isosceles Triangle Medians

Use coordinate geometry to prove that the medians drawn to both legs of an isosceles triangle are congruent. That is, write a coordinate geometry proof that formally proves what this applet informally illustrates. Be sure to assign appropriate variable coordinates to key points on this isosceles triangle! (The maximum number of variable coordinates your coordinate setup should have is 2.)
Now prove this same theorem true using the format of a 2-column proof or a paragraph proof. Hint: This proof will contain multiple pairs of congruent triangles.

Quick (Silent) Demo