The solution of the problem 2.8 cr 2 from the problem b

The solution of the problem 2.8 cr 2 from the problem b

Task 2.8
Charges of 1 nC are placed at the vertices of an equilateral one; Triangle with a side of 0.2 m.
Equal force acting on the fourth charge placed on the middle of one side
Triangle is 0.6 μN. Determine this charge of the strength and potential of the field at its point
Location.