The points (a,a), (−a,−a) and (–√3a,√3a) form the vertices of an
Equilateral triangle
Let the points be A(a,a), B(−a,−a), C(–√3a,√3a)
Using distance formula,
BC=√(a+√3a)2+(a−√3a)2=2√2a
AB=√(a+a)2+(a+a)2=2√2a
AC=√(−a+√3a)2+(−a−√3a)2=2√2a
We got AB=BC=AC=2√2a
ABC is an equilateral triangle