Is the triangle whose vertices are the points A(0 , -1) , B(2 , 1) and C(-4 , 3) a right triangle?

The triangle ABC has vertices at A(0, -1) , B(2 , 1) and
C(-4, 3).

The length of the sides
is

AB = sqrt [(2 - 0)^2 + (1 +
1)^]

=> sqrt (4 + 4) = sqrt
8

BC = sqrt[(2 + 4)^2 + (3
-1)^2]

=> sqrt( 36 + 4) = sqrt
40

CA = sqrt [( 4 - 0)^2 + ( 3 +
1)^2]

=> sqrt (16 + 16) = sqrt
32

As CA^2 + AB^2 = BC^2, by the Pythagorean theorem we
know that the triangle is a right triangle with hypotenuse
BC.

The triangle ABC is a right
triangle.