Question

Two Concentric circles of radii a and b (a>b) are given. Find the length of the chord of the larger circles which touches the smaller circles.? ​

Answer 1

here,

in triangle ACB,

AC is perpendicular to BC ( tangent is perpendicular to radius of circle at the point of contact)

by Pythagoras theorem,

AB^2= AC^2 + BC^2

with this u can find the value of BC

Then,

length of chord BD= BC +CD

= BC+ BC

= 2BC