Question

If a, b, & c are sides of a ∆ABC and

$\left| \begin{matrix} a^{2} & b^{2} & c^{2} \\ (a + 1)^{2} & (b + 1)^{2} & (c + 1)^{2} \\ (a - 1)^{2} & (b - 1)^{2} & (c - 1)^{2} \end{matrix} \right| = 0$, then

• A. ∆ABC is an equilateral triangle`
• B. ∆ABC is a right angled triangle
• C. ∆ABC is an Isosceles triangle
• D. None of these

Answer 1

Answer: (C)

∆ABC is an Isosceles triangle

Answer 2

When a = b or b = c or c = a the determinant reduces to zero.

It is not necessary that a = b = c for determinant to be zero. Therefore triangle is isosceles