Question

The quantities x and y are proportional. Find the constant of proportionality r in the equation y = rx

Answer 1

r = 7

Explanation:

To solve this, we can plug in a pair of x and y values and solve for r.

y = rx | Plug in a pair

42 = r*6 | Now divide both sides by 6

7 = r.

We can test this by plugging in r with a pair.

y = (7)x

77 = 7*11, 77 = 77, This equation is correct.

Answer 2

The constant of proportionality r in the equation is:

r = 7

Explanation:

We know that for the equation of the type:

`y=rx`

The constant of proportionality is given by the equation:

`r=(y)/(x)`

i.e. it is the ratio of the output to the input values.

Here we have a table of values as follows:

x y

2 14

6 42

11 77

Hence, with the help of any one set of value we will get the value of r.

We take the set (2,14)

i.e.

`r=(14)/(2)\\\\r=7`