Question

The point P is equidistant from A(1, 3),B(– 3, 5) and C(5, – 1) then PA is equal to-

• A. 5
• B. $5\sqrt{5}$
• C. 25
• D. $5\sqrt{10}$

Answer 1

Answer: (D)

$5\sqrt{10}$

Answer 2

Let , P(x₁, y₁) is circumcentre of DABC…

Ž PA = PB = PC

Ž $\left\{ \begin{aligned} & PA^{2} = PB^{2}.....(1) \\ & PB^{2} = PC^{2}.....(2) \end{aligned} \right.\$

Solve (1) & (2)

Ž $\left\{ \begin{aligned} & x_{1} = ? \\ & y_{1} = ? \end{aligned} \right.\$ PA = $5\sqrt{10}$ units