Answer:

Explanation:
In this question, we're going to need to solve the equation for r.
This means that we need to get the r by itself to see what it equals to.
Lets solve:

When you're done solving, you should get r = 4
This means that the value of r is 4 (or r = 4)
I hope this helped you out.
Good luck on your academics.
Have a fantastic day!