Question

if r1 and r2 are radii of two concentric circles if chord of larger circle AB touches the inner circle.Find the value of AB is what?​

Answer 1

Step-by-step explanation:

the value of ab is90° because of a theoram

the angles substended by two equal chords are always 90°

Answer 2

Answer:

Given : r1 and r2 are the radii of two concentric circles and r1> r2

AB is chord of larger circle touches the inner circle

To Find : Length of AB

Solution:

AB is chord of circle

and touches other circle , let say at M

and O is center of both circles

Then OM⊥ AB ( as AB is tangent)

also AB is chord hence M is mid point of AB

AM² = OA² - OM²

OA = r₁ ( radius of larger circle)

OM = r₂ ( radius of smaller circle)

=> AM² = r₁² - r₂²

AM = √(r₁² - r₂²)

AB = 2AM = 2 √(r₁² - r₂²)