Are the points A(3,6,9) B(10,20,30) and C(25,-41,5)the vertices of a right angled triangle

Show that the points A=(2,-1,1),B=(1,-3,-5) and C=(3,-4,-4) are vertices of a right angled triangle (using vector method).

Show that the points (6,6) , (2,3) and (4,7) are the vertices of a right angled triangle

Show that the points (3,0),(6,4) and (-1,3) are the vertices of a right angled isosceles triangle.

Without using the Pythagoras theorem, show that the points (4,4), (3, 5) and (-1, -1) are the vertices of a right angled triangle.

Prove that A(3,3) B (8,-2) and C(-2,-2) are the vertices of a right - angled isosceles triangle . Also, find the length of the hypotenuse of triangle(ABC)

Prove that the points (1,-3,1), (0,1,2), (2,-1,3) are the vertices of an isosceles right angled triangle

Show that the points (0,7,10), (-1,6,6) and (-4,9,6) are the vertices of a right angled isosceles triangle.

Calculating the angle of the triangle, prove that the points A(3, 4, -1) , B(1, 5, 1) and C(1, 2, -2) are the vertices of an isosceles triangle.

The points (0,8/3),(1,3) and (82 ,30) are the vertices of (A) an obtuse-angled triangle (B) an acute-angled triangle (C) a right-angled triangle (D) none of these

Let A(0,beta), B(-2,0) and C(1,1) be the vertices of a triangle. Then Angle A of the triangle ABC will be obtuse if beta lies in