Answer:
1
Explanation:
Slopes of perpendicular lines are opposite reciprocal of one another i.e.
slope m1, of given line l1 = -1/slope m2, of its perpendicular line l2
slope m2, of its perpendicular line l2 = -1/slope m1, of given line l1
m2= -1/m1
Finding m1 from the given graph
m1= y2-y1/x2-x1
= -2-1/2+1
= -3/3
= -1
m2= -1/-1
= 1 !