Checking and understanding graphs showing direct proportion

12 questions

1. If two variables share a constant multiplicative relationship they are in direct ___ to one another.
2. In this example how can you tell that the variables x and y are not in direct proportion?
3. The cost of hiring headphones at a festival is directly proportional to the time you hire them for. If two hours cost £16, how much should five hours cost?
4. The gradient of a straight line that passes through coordinates (10, 18) and (17, 53) is ___
5. What is the equation of this line?
6. Find the equation of the straight line that goes through coordinates (8, -1) and (12, 1).
7. Graphs of direct proportion intersect the axes at the ___.
8. Graphs of direct proportion begin at the origin and ...
9. Select the graphs that represent direct proportion.
10. For the coordinates (8, 20) and (10, 25), x and y are in direct proportion. Which of these coordinates also represent this same direct proportion?
11. The point P lies on this direct proportion graph. The y-coordinate of P is 25, the x-coordinate of P is ___.
12. The point P lies on this direct proportion graph. The x-coordinate of P is 375. Which of these calculations can you use to find the y-coordinate of P?

License: OGL