Answer:
4/7
Explanation:
If the slope of line d is -7/4, then the slope of a perpendicular is 4/7.
Given a slope, to find the slope of a perpendicular, flip the fraction and change the sign.
Flip -7/4 to get -4/7. Then change the sign of -4/7 to get 4/7.
Answer: 4/7