Locus of Points with Constant Angle

angle θ

1.0472

This Demonstration plots the points for which line segments drawn from two fixed points on the

x

axis have angle

θ

. The locus consists of the arcs of two circles, with centers that move along the

y

axis as you vary

θ

. For

θ=90°

, the arcs are semicircles and the locus is a circle.