Q. Consider the circle $W = x^{2} + y^{2} = 81$ . Let $A B$ be a diameter of circle $W$ . $A B$ is extended through $A$ to $C$ . Point $T$ lies on W so that line CT is tangent to W. Point P is foot of perpendicular from A to the line CT. Then the last digit of maximum value of $(BP)^{2}$ is -

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Answer: 2

Solution:

Q. Consider the circle W=x2+y2=81. Let AB be a diameter of circle W. AB is extended through A to C. Point T lies on W so that line CT is tangent to W. Point P is foot of perpendicular from A to the line CT. Then the last digit of maximum value of (BP)2 is -