Question

In the given figure, PS is a tangent and line PR is a secant to the circle. If PQ = 4.9 cm and QR = 5.1cm, then PS = ______cm.

• A. 7
• B. 10
• C. 49
• D. 4.9

Answer 1

The correct option is A 7

$P{S}^2=PQ\times PR$ ...(Tangent secant segments theorem)
$P{S}^2=PQ\times (PQ+QR)$
= 4.9 (4.9 + 5.1)
= 4.9 x 10 = 49
$\therefore PS=7cm$