Multiple choice

A tangent is drawn from a point M to a circle, which meets the circle at T such that MT = 12 cm. A secant MAB intersects the circle at points A and B. If MA = 8 cm, what is the length (in cm) of the chord AB ?

  1. 16

  2. 10

  3. 12

  4. 9
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

By the tangent-secant power theorem: MT^2 = MA × MB. Given MT = 12, MA = 8, we get 144 = 8 × MB, so MB = 18. Since AB = MB - MA, AB = 18 - 8 = 10cm. Option A (16cm) would be the whole secant MB. Option C (12cm) is the tangent length. Option D (9cm) doesn't match the calculation.

Keep practicing — related questions