# Similar triangles. How does 4/6 turn into 2h/3 ?

1. Nov 5, 2012

### nukeman

1. The problem statement, all variables and given/known data

r/h = 4/6

This turns into: r = 2h/3

How, can someone please refresh me? I am doing a related rates problem, and I for this! :(

2. Relevant equations

3. The attempt at a solution

2. Nov 5, 2012

### dextercioby

Isn't 4/6 = 2/3 ? (Everything is written in basis 10).

3. Nov 5, 2012

### Staff: Mentor

r/h = 4/6 = 2/3

Now multiply both sides of this equation by h.

4. Nov 5, 2012

### nukeman

4/6 * x = 2x/3x ?

Why is just 2x/3 ?

5. Nov 5, 2012

### dextercioby

The multiplication affects only the numerator. Think about it as (6/4)x5 = (6:4)x 5 = 6:4x5 = 6x5:4 = 30:4 = 7.5

Last edited: Nov 5, 2012
6. Nov 5, 2012

### HallsofIvy

Staff Emeritus
If you are doing things involving "related rates" and Calculus, I think we have right to assume that you can do arithmetic! 4/6= (2*2)/(2*3)= 2/3!!!

7. Nov 5, 2012

### Staff: Mentor

And if this assumption by us is incorrect, then you are going to have a very difficult time in calculus.