PM and PN are two tangents of a circle from an external point P, M and N are points on the circle. If PM = y2 - 9 and PN = 55, then what is the value of y?

64 17 8 12

8

Concept Tangents are equal in length drawn from an outside point on the circle. Calculation According to the concept, PM = PN   (Tangents are equal) \( {y }^{2 } \) - 9 = 55 \( {y }^{2 } \) = 55 + 9 = 64 y = 8, Therefore y is 8.