Question

Find the unknown length x of the following figure.

• A. 2 cm
• B. 18 cm
• C. 10 cm
• D. 12 cm

Answer 1

The correct option is B

18 cm

When two chords of a circle intersect internally or externally, then the products of the lengths of segments are equal.

i.e. PA x PB = PC x PD

$\Rightarrow 8\times 9=4\times x$
$\Rightarrow \frac{72}{4}=x$
$\Rightarrow 18=x$
$\therefore$ PD = x = 18 cm