Three equal charges, each +q, are placed on the corners of an equilateral triangle. The electric field intensity at the centroid of the triangle is

Enet 1=2Ecosθ2=2Ecos1202=2Ecos60=E upwards Enet 2=E downwards Enet =E-E=0Each charge will produce the same magnitude of intensity, say E, at the centroid. These are directed at angles of 1200 with each other. So, their vector sum will be zero.