Answer:
AB = 4 cm
Step-by-step explanation:
The tangent and secant are drawn from an external point to the circle.
Then the square of the measure of the tangent is equal to the product of the external part of the secant and the entire secant.
let AB = x, then
x(x + 5) = 6²
x² + 5x = 36 ( subtract 36 from both sides )
x² + 5x - 36 = 0 ← in standard form
(x + 9)(x - 4) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 9 = 0 ⇒ x = - 9
x - 4 = 0 ⇒ x = 4
However x > 0 ⇒ x = 4 ⇒ b = 4 CM
