Finding the side of equilateral triangle when the distances from a point inside the triangle is given

Given a point inside an equilateral triangle and its distance from the three vertices. How do you find the side of the equilateral triangle ?
To find the length of the equilateral triangle
1. Construct the triangle with the sides (the distance from the vertex)
2. Draw an equilateral triangle on one of the side of this triangle. This forms a quadrilateral.
3. Measure the diagonal of this quadrilateral and that will be the side of the original equilateral triangle

I have used KSEG here to draw an equilateral triangle and chosen a point. Now I have also drawn the triangle on the same using vector function