The variable z is directly proportional to x. when x is 13, z has the value 169. what is the value of z when x = 19?

Given that, the variable z is directly proportional to x.

So, we can set up an equation as following:

z = kx Where k is constant of variation.

When x= 13, z is 169.

Hence, next sep is to plug in these values in the above equation to get the value of k. Therefore,

169 = k * 13

Divided each sides by 13.

So, k = 13

By plug in k = 13 in the above equation we will get z = 13x.

Now we need to find the value of z when x = 19.

From the above equation we will get:

z = 13 * 19

z = 247

So, z = 247.

I hope this helps you!

the graph top, left is y = 4x