Consider two concentric circles having radii 17 cm and 15 cm. What is the length (in cm) of the chord, of the bigger circle, which is a tangent to the smaller circle?

Correct option is A

Given:
Radius of circles $$r_1$$​= 15 cm
$$r_2$$​= 17 cm
Concept Used:
Property of tangent - A tangent is perpendicular with the center of the circle.
Property of chord - A perpendicular line drawn from the center of the circle to the chord of the circle always divide the chord in half.
Solution:

Applying the property of chord and tangent:
We find that-
​$$17^2 = 15^2+(\frac{x}{2})^2 \\\ \\289 = 225 + (\frac{x}{2})^2\\\ \\289 – 225 = (\frac{x}{2})^2 \\\ \\√64 = (\frac{x}{2})\\\ \\\frac{x}{2}=8$$​​
Therefore, length of the chord x = 16 cm.