-1

How to find the length of the tangent to the circle $x^2+y^2=4$ drawn from the image of origin w.r.t $3x+4y+25=0$.

The options given are

  1. $96$

  2. $\sqrt{96}$

  3. $9\sqrt{6}$

  4. $6\sqrt{8}$

Dashi
  • 791
  • 5
  • 12
Mithilesh
  • 103
  • What do you mean by "the image of a point w.r.t. a line"? –  Sep 06 '18 at 00:56
  • That is the place where I got confused and I asked here – Mithilesh Sep 06 '18 at 00:58
  • Please try to make the titles of your questions more informative. For example, Why does $a<b$ imply $a+c<b+c$? is much more useful for other users than A question about inequality. From How can I ask a good question?: Make your title as descriptive as possible. In many cases one can actually phrase the title as the question, at least in such a way so as to be comprehensible to an expert reader. You can find more tips for choosing a good title here. – Shaun Sep 06 '18 at 01:06
  • You'll find that simple "Here's the statement of my question, solve it for me" posts will be poorly received. What is better is for you to add context (with an [edit]): What you understand about the problem, what you've tried so far, etc.; something both to show you are part of the learning experience and to help us guide you to the appropriate help. You can consult this link for further guidance. – Shaun Sep 06 '18 at 01:06

1 Answers1

0

The tangent is drawn from the reflection of the origin in the line $3x + 4y + 25 = 0$.

I'll leave you to figure out how the lengths relate to the answer $x = \sqrt{10^2 - 2^2} = \sqrt(96)$ in the sketch below.

enter image description here

Phil H
  • 5,579