a x=6 angle measure is 36
b x=9 angle measure is 36
c x=6 angle measure is 54
d x=9 angle measure is 54

Answer:
A
Step-by-step explanation:
6x° and 54° form the angle of 90° , that is
6x + 54 = 90 ( subtract 54 from both sides )
6x = 36 ( divide both sides by 6 )
x = 6
then
6x = 6 × 6 = 36°