Can someone me and show me how to solve this?

in the figure, yx is a tangent to circle o at point x.

mxb = 52°
mxa = 104°

what is the measure of ∠xya?

i can't remember how to solve questions like this since it's been a while. in advance.

Need ! a certain ultraviolet ray has a frequency of 1 × 1016 hz, and a certain infrared ray has a frequency of 2 × 1012 hz. which of the following is true? a. the frequency of the ultraviolet ray is fifty thousand times the frequency of the infrared ray. b. the frequency of the infrared ray is fifty thousand times the frequency of the ultraviolet ray. c. the frequency of the ultraviolet ray is five thousand times the frequency of the infrared ray. d. the frequency of the infrared ray is five thousand times the frequency of the ultraviolet ray.