Question:
From a point Q, the length of the tangent to a circle is 24 cm and the distance of Q from the centre is 25 cm. The radius of the circle is -
(A) 7 cm
(B) 12 cm
(C) 15 cm
(D) 24.5 cm
Solution:
From figure,
$r^{2}=(25)^{2}-(24)^{2}$
$=625-576$
$=49$
$\Rightarrow \mathrm{r}=7 \mathrm{~cm}$
Hence, the correct option is (A)