Question

Variable y varies directly with variable x, and y = 9 when x = 5.

What is the constant of variation in decimal form?

Answer 1

Direct variation:


`\sf~y=kx`

Plug in what we know:


`\sf~9=k(5)`


`\sf~9=5k`

Divide 5 to both sides:


`\sf~k=\boxed{\sf1.8}`

So the constant of variation is 1.8.