Question

Find electric field intensity at the centre of the triangle

Answer 1

Three identical point charges each of charge q are located at the vertices of an equilateral triangle as in the figure. The distance from the center of the triangle to each vertex is a. (a) Show that the electric field at the center of the triangle is zero.

Answer 2

If I understand your problem correctly, the electric field will be zero. That is because due to symmetry, the electric field from each particle perfectly cancels each other when added. This will happen any time you have particles evenly distributed around a centroid.