Answer:
The correct option is A.
Step-by-step explanation:
Line A and B are parallel lines.
\(\angle 1=3x\) ....(1) (Alternate exterior angles)
\(\angle 1+9x=180\) (Supplementary angles)
\(3x+9x=180\)
\(12x=180\)
\(x=15\)
The value of x is 15.
Put this value in equation (1).
\(\angle 1=3\times 15=45\)
Therefore measures of angle 1 is 45° and option A is correct.
