Answer:
x=20
Step-by-step explanation:
we know that
Triangles YNF and YUN are congruent by SSS
Because
YN=YF=YU=r -----> the radius of the circle
FN=NU ----> given problem
therefore
∠FYN=∠NYU
and
arc FN=∠FYN -----> by central angle
arc NU=∠NYU -----> by central angle
so
arc FN=arc NU
substitute the given values
5x-10=3x+30
solve for x
5x-3x=30+10
2x=40
x=20
