Answer:
B
Step-by-step explanation:
y and [tex]\frac{1}{2}[/tex] x + 20 are corresponding angles and are congruent, then
y = [tex]\frac{1}{2}[/tex] x + 20 → (1)
2x - 10 and y are adjacent angles and supplementary, sum to 180°, so
2x - 10 + [tex]\frac{1}{2}[/tex] x + 20 = 180, that is
[tex]\frac{5}{2}[/tex] x + 10 = 180 ( subtract 10 from both sides )
[tex]\frac{5}{2}[/tex] x = 170 ( multiply both sides by 2 to clear the fraction )
5x = 340 ( divide both sides by 5 )
x = 68
Substitute x = 68 into (1)
y = [tex]\frac{1}{2}[/tex] (68) + 20 = 34 + 20 = 54° → B
