Question

which line has a constant of proportionality between y and x of 5?
graph with lines a, b, c
choose 1 answer:
a a
b b

Explanation:

Step1: Recall proportionality formula

For proportional relationships, $y = kx$, where $k$ is the constant of proportionality ($k=5$ here, so $y=5x$).

Step2: Test line A with a point

Take $x=2$, substitute into $y=5x$: $y=5\times2=10$. Line A reaches $y=10$ at $x=2$, which matches.

Step3: Verify other lines (optional check)

For line B: At $x=2$, $y\approx5$, so $k=\frac{5}{2}=2.5
eq5$. For line C: At $x=2$, $y\approx2$, so $k=\frac{2}{2}=1
eq5$.

Answer:

A. A