Question

How to find a third vertex of equilateral triangle if two vertex are given?

Answer 1

subtract the sum of two vertex from 180degree .then you will get the answer

Answer 2

$x1 + x2 + \sqrt{3} (y1 - y2) \div 2 \: \: y1 + y2 - \sqrt{3} (x1 - x2)$