## A community for students. Sign up today

Here's the question you clicked on:

## anonymous 3 years ago Assume F is directly proportional to r, and F = 11 when r = 3. Find the equation that relates F to r. I'm awful at math please help me!

• This Question is Closed
1. Mr.Math

You'll like this; it's very nice! When we say that F is directly promotional to r, that means we can write relate them by an equation similar to this $$F=kr$$. Our task here is to find what the value of k is.

2. Mr.Math

But we're already given that $$F=1$$ when $$r=3$$. So we can write: $$11=k\times 3$$ Now divide both sides by 3, you get $\frac{11}{3}=k.$

3. Mr.Math

Now substitute that for k in that equation, and you're done: $F=\frac{11}{3} r$

4. anonymous

Ahh gotcha =) thanks

5. Mr.Math

Isn't it fun?

6. anonymous

It is now that I understand it! Thank you!!! =)

7. Mr.Math

I'm glad to hear (*read) that.

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy