O is the center of a circle with a diameter of 16 cm. Q is a point outside the circle and QS is tangent to the circle at point S. If OQ is = 17 cm, what is the length (in cm) of the tangent QS?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 15.
Radius (OS) = 16/2 = 8 cm
OQ = 17 cm
∠OSQ = 90°
In ΔOSQ, QS = √(OQ2 - OS2) = √(172 - 82) = √(289 - 64) = √225 = 15 cm
Hence, the length of the tangent QS is 15 cm.