Explanation

(a)
Given that, $5x - 12y + 10 = 0$ …(i)
And $- 5x + 12y + 16 = 0$ …(ii)
Slope of Eq. (i), $= \frac{5}{12}$
Slope of Eq. (ii)$= \frac{5}{12}$
Thus, Eqs. (i) and (ii) are parallel
Therefore, distance between parallel lines = diameter of the circle
$\Rightarrow \ \ \ \frac{|10 + 16|}{\sqrt{25 + 144}} = 2 \times$ radius of the circle
$\Rightarrow$ 2 radius of circle $= \frac{26}{13}$
$\Rightarrow$ Radius of circle=1