Controlling answer box for Numeric Question

Is it possible to change the font size and also the alignment for the text where students will type in their answer? And if so, how?

I have an equation I want students to solve, and I resized the answer box (made it bigger) and moved it to appear on the right side of the equation. When I preview/publish and type in the answer, it appears in tiny font and pushed up in the upper left corner of the box.

I had right-clicked on the box (in Slide View mode) and selected Format Shape. Then on the Text Box tab, I selected "middle" for vertical alignment. But this setting did not appear to hold when I actually went back to test the question.

I also tried right clicking on the box, selecting Edit Text, and then increasing the font size. Again, the setting did not hold when I previewed/published.