Show that the points and form an isosceles triangle.

Let, and be the position vectors corresponding to the vertices A, B and C of ΔABC.

Recall the vector is given by

Recall the magnitude of the vector is given as

Now, we find the magnitude of .

Similarly, the vector is given by

Now, we find the magnitude of .

Similarly, the vector is given by

Now, we find the magnitude of .

Observe that which means the sides AB and AC of ΔABC are equal in length, making it an isosceles triangle.

Thus, the triangle formed by the given points is isosceles.