Question:
If the angle of intersection at a point where the two circles with radii $5 \mathrm{~cm}$ and $12 \mathrm{~cm}$ intersect is $90^{\circ}$, then the length (in $\mathrm{cm}$ ) of their common chord is :
Correct Option: , 2
Solution:
Let length of common chord $=2 x$
$\sqrt{25-x^{2}}+\sqrt{144-x^{2}}=13$
after solving
$x=\frac{12 \times 5}{13}$
$2 x=\frac{120}{13}$