Answer:
Based on the given information, if ∠1 measures 135°, the measure of ∠6 would be 45°. This is because ∠1 and ∠6 are corresponding angles formed by the transversal line d intersecting parallel lines b and c. Corresponding angles are congruent when formed by a transversal intersecting parallel lines, meaning that they have the same measure. Therefore, if ∠1 measures 135°, ∠6 must also measure 135°.