question_answer

A circle \[{{x}^{2}}+{{y}^{2}}-6x-16=0\] cuts the x-axis at A and B and positive y-axis at the point D (0, d). The value of d equals

A)  2                                

B)  4

C)  9                                

D)  16

Correct Answer: B

Solution :

\[\Rightarrow \,\frac{d}{2}\,.\frac{d-0}{0-8}\,=-1\]\[\Rightarrow \,{{d}^{2}}=16\,\,\,\Rightarrow \,\,d=4\]