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?
Answer & explanation
Correct answer: option 3
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.