To find the constant of proportionality k we have to pick 2 points from the table. This points (x1,y1) and (x2,y2) will give the constant like:
I'll pick the first two points:
• x1 = 6
,
• y1 = 21
,
• x2 = 7
,
• y2 = 24.5
The constant of proportionality is k = 3.5