Chord of a circle is $8cm$ in length & its distance from the centre is $3cm$. Find the radius of the circle.

Length of chord $8$

Distance from center $3$

Length of chord is given by- $2\sqrt{r^2-d^2}$

$2\sqrt{r^2-3^2}=8$

$\sqrt{r^2-3^2}=4$

$r^2-9=16r^2=16+9r^2=25r=\sqrt{25}r=5$