Final answer:
To find the missing coordinate r, apply the slope formula and solve for r, yielding the result r = 1.
Step-by-step explanation:
To find the missing coordinate r for the point (-3, r) on a line with a slope of 1/4 that also passes through the point (9, 4), we can use the slope formula:
m = (y2 - y1) / (x2 - x1)
Plugging in our known values, we get:
1/4 = (4 - r) / (9 - (-3))
This simplifies to:
1/4 = (4 - r) / 12
We then cross-multiply to find the value of r:
1(4 - r) = 1/4(12)
4 - r = 3
r = 4 - 3
r = 1
Therefore, the missing coordinate r is 1.