PowerPoint delimma--matching colors

I am working on a PowerPoint presentation, and on one page, I have a cyan block of text next to a cyan rectangle. Here is the problem: even though I selected the same color for both of them, the text color appears as a nice, bright cyan while the cyan color of the rectangle shape looks dulled. I turned off all shadowing, inner glow, etc, but just can't seem to get the rectangle cyan to match the text cyan! HELP!