Multiple choice

The equation of pair of tangents from origin to a circle is $24xy + 7y^{2} = 0$. If the radius of the circle is 3 , then the length of the tangent drawn from the origin is

  1. $7$
  2. $24$
  3. $3$
  4. $4$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The equation of the pair of tangents is 24xy + 7y^2 = 0, which factors to y(24x + 7y) = 0. This gives two lines: y = 0 and y = -24/7 x. The distance from the center (h, k) to these lines must equal the radius 3. Solving for the center and then the distance from the origin yields 4.

Keep practicing — related questions