We know that: $$TC = TFC + TVC$$ Dividing both the sides by 'Q', we get $$dfrac{TC}{Q} = dfrac{TFC}{Q} + dfrac{TVC}{Q}$$ $$ATC = 0 + AVC$$    $$[ herefore TFC = 0]$$ Hence, $$ATC = AVC$$ Graphically, both the cost curves will intersect each other.