Question

Two concentric circles having radii $7$ and $25$ are given. The chord of the circle with larger radius touches the circle with smaller radius, then find the length (in cm) of the chord.

Answer 1

REF.Image

$AB=?$

In $\Delta OAC$-

$O{A}^2={\alpha }^2+A{C}^2$

${25}^2=7^2+A{C}^2$

$A{C}^2=625-49=576$

$AC=24$

Similarly

In $\Delta OCB$-

$O{B}^2=O{C}^2+B{C}^2$

${25}^2=7^2+B{C}^2$

$B{C}^2=625-49$

$BC=24$

$AB=AC+CB$

$AB=48cm$