Direct & Inverse Proportion Quiz

1. $y$ is directly proportional to $x$. If $y = 12$ when $x = 4$, what is $y$ when $x = 9$?

• A. A. 24
• B. B. 27
• C. C. 36
• D. D. 3

2. $y$ is inversely proportional to $x$. If $y = 5$ when $x = 8$, what is $y$ when $x = 4$?

• A. A. 2.5
• B. B. 40
• C. C. 10
• D. D. 20

3. Which type of graph represents $y = \dfrac{k}{x}$ for a positive constant $k$?

• A. A. A straight line through the origin
• B. B. A parabola
• C. C. A reciprocal curve
• D. D. A straight line not through the origin

4. $y$ is directly proportional to $x^2$. If $y = 45$ when $x = 3$, find $y$ when $x = 6$.

• A. A. 90
• B. B. 180
• C. C. 360
• D. D. 45

5. $y$ is inversely proportional to $\sqrt{x}$. If $y = 8$ when $x = 4$, find $y$ when $x = 16$.

• A. A. 4
• B. B. 16
• C. C. 2
• D. D. 32