If you understand the question clearly then you solve the above problem.
We know the equation of a tangent in terms of slope form
i.e.,

Squaring on both sides, we get
For the lines to make complemetary angles with the x-axis the product of the roots of above equation is equal to -1
i.e.,,m1m2 = -1
On simplifying you get the equation of a circle known as director circle
x2+y2=2a2 [since here r=a]
Approve my answer if it helped you.