Net electric field with triangle

[nothingatall]

Homework Statement

A proton and an electron form two corners of an equilateral triangle of side length 5.3 x 10-6 m. What is the magnitude of the net electric field these particles produce at the third corner?

Homework Equations

E=kQ/r^2

The Attempt at a Solution

I drew a triangle with an electron and a proton as the corners. I'm thinking of using Pythagorean theorem or something then solve this with the formula by dividing the distance. I'm sort of confused but i do know that the answer will be negative.

 

[minimark1234]

hopefully this can point you in the correct direction to go into solve this problem. one of the main concepts in electrodynamics is superposition. superposition says that the electric field at a point is the sum of all the electric charges acting on that point. hopefully the fact the electrostatics follows the rule of superposition you might have a slight idea how to approach this problem.