[2](a)y is directly proportional to x². When x = 3, y = 18. Find the formula connecting y and x.

[1](b)Use your formula to find y when x = 5.

[2](a)p is inversely proportional to q. When q = 4, p = 9. Find p when q = 6.

[3](a)y is directly proportional to √x. When x = 9, y = 12. Find y when x = 25.

[3](a)F is inversely proportional to r². When r = 2, F = 20. Find F when r = 4.

[3](a)p varies directly as q³. When q = 2, p = 40. Find p when q = 3.

[2](a)State whether 'the time to complete a job' and 'the number of workers' (working at the same rate) are directly or inversely proportional, and explain why.

[2](a)p is directly proportional to q. When q=4, p=20. Find p when q=9.

[2](a)y is inversely proportional to x. When x=5, y=8. Find y when x=10.

[2](a)z varies as the square of w. When w=3, z=27. Find z when w=5.

[1](a)Explain what it means for two quantities to be in direct proportion.