Question

If y is proportional to the square root of x and y is=21 when x=49 find y when x =144

Answer 1

y = 36

Explanation:

Because the problem says y is proportional to the square root of x, we can assume that it is directly proportional.

The general formula for direct proportionality is

`y=kx`, where k is the constant of proportionality.

Taking into account the square root of x, we can use the following formula to find k by plugging in x and y:

`y=k√(x)\\ 21=k√(49)\\ 21=7k\\3=k`

Since we found k, we can now use this value and the x we're given for the second part of the problem to find y:

`y=3√(x) \\y=3√(144)\\ y=3*12\\y=36`