Three equal point charges, each with charge 1.60 , are placed at the vertices of an equilateral triangle whose sides are of length 0.450 . What is

Three equal point charges, each with charge 1.60 , are placed at the vertices of an equilateral triangle whose sides are of length 0.450 . What is the electric potential energy of the system? (Take as zero the potential energy of the three charges when they are infinitely far apart.)