[TYPO3-english] Problem with increasing font size of the text in TYPO3 4.1.5

[harishathreya .]

Hi,
 I am facing a problem with my TYPO3 4.1.5. On pages having text, i am not
able to increase the font size.
I am not able to change the size of the text to (default+1 or so...) and
other properties. I suppose this has got to do with enabling some property
of RTE. Please let me know how do i solve this problem.

Thanks a lot,
Harish.