If you have an element with the font size of 18px, and a child element inside with a font-size set to .5em, what is the font size of the child in px?

To determine the font size of the child element when it is set to .5em, it's important to understand how the 'em' unit works in relation to the font size of a parent element. The 'em' unit is relative to the font size of the element on which it is applied.

In this case, the parent element has a font size of 18px. When the child element is styled with a font size of .5em, it means that its font size will be half of the parent element's font size. Therefore, you can calculate the font size of the child element as follows:

0.5em = 0.5 * 18px

This calculation gives you:

0.5 * 18px = 9px

Consequently, the font size of the child element is 9px. This understanding of how em units relate to their parent elements is crucial in responsive web design and allows developers to create scalable and flexible layouts.