Answer:
75°
Explanation:
Poloygon ABCD slides 4 units left and 3 units up on the coordinate plane. This means that the transformation applied to the polygon is translation 4 units left and 3 units up.
A translation is a rigid transformation. Each rigid transformation preserves the measures of angles. If the original measure of angle A was 75°, then the measure of angle A after translation is 75° too.