Mathematics

Problem

\mathbf{x}

and

\mathbf{y}

are two non-collinear vectors and ABC is a triangle with side lengths

a, b

and

c

satisfying

(20a - 15b)\mathbf{x} + (15b - 12c)\mathbf{y} + (12c - 20a)(\mathbf{x} \times \mathbf{y}) = \mathbf{0}

, then

\Delta ABC

is a. an acute angled triangle b. an obtuse angled triangle c. a right angled triangle d. a scalene triangle