Prove that in an isoceles triangle two of the medians (the lines drawn from the vertex to the midpoint of the opposite side) are congruent.
Let ABC be an isosceles triangle with AB = AC
Draw median BM to side AC and median CN to side AB
Note that since AB = AC...then then the medians divide AB and AC into two equal parts.....so....MC = NB
And since AB = AC, then angle ABC = angle ACB
And BC = BC
So...by side-angle side.....triangle MCB is congruent to triangle NBC
So...therefore....BM = CN
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