Answer:
It might be 8.8889% (Not completely sure)
https://cdn.kutasoftware.com/Worksheets/PreAlg/Reflections%20of%20Shapes.pdf
Step-by-step explanation:
pls search this
false false true false ez
x = 21.8°
tan = opposite / adjacent
tan x = 8/20
tan^-1 = 21.8°