Answer:
The answer is 12.
Step-by-step explanation:
The question says QS is a tangent to circle P which means to QS is perpendicular 90° to QS. With provided information, we are able to find the value of QS using Pythogoras' Theorem, a²+b² = c² :
Let c = PR+RS = 5+8 = 13 units,
Let b = PQ = 5 units,
Let a = QS,
13² = 5² + QS²
QS² = 13² - 5²
= 169 - 25
= 144
QS = √144
= 12 units
