How Does Molar Mass Affect Gas Molecule Speeds at Equal Temperatures?

[Gimp]

If the translational rms speed of the water vapor molecules (H2O) in air is 676 m/s, what is the translational rms speed of the carbon dioxide molecules (CO2) in the same air? Both gases are at the same temperature.

So what I have so far...

VrmsH20 = squareroot of 3RT/mCO2
VrmsCO2 = squareroot of 3RT/mCO2

676 = squareroot of mCO2/mH2O

And I already found the mass of the CO2 and H2O, but then I'm stuck... Can anyone help please?

 

[Psi-String]

$$V_{rms} = \sqrt{\frac{3RT}{M}}$$

since the temperature is the same, think proportion.