Point a is the point of concurrency of the angle bisectors of δdef. what is the length of za? za = 3cm za = 4cm za = 5cm za = 6cm

The picture in the attached figure

we know that
The angle bisectors of a triangle intersect in a point (incenter) that is equidistant from the three sides of the triangle
so
ZA=YA=XA-----> are the radii of the inscribed circle
XA=3 cm

therefore
ZA=3 cm

the answer is
ZA=3 cm

(-r, θ+ pi) & (r, theta-2pi)