Let A(1, 2) and B(7, 10) are two points. If P(x, y) is a point such that the ∠APB is 60∘ and the area of the △APB is maximum, then which of the following is/are true.
P lies on the perpendicular bisector of AB
P lies on the straight line 3x + 4y = 36
For the area to be maximum, P should lie on the perpendicular bisector of the side AB.
Mid-point of AB= (7+12, 10+22)=(4, 6)
Slope (AB)= 86=43
∴ Slope of ⊥ bisector = −34
Thus equation of line on which P lies is
y−6=−34 or 3x+4y=36
Since, the angle subtended is constant, AB would a chord with P being the trace of the circle.
For max area, △ABP would be equilateral.
Length of AB=10
∴ Radius of the circle =23⋅√32⋅10=10√33