Using Atto - The Moodle Editor
Accordions or collapsing regions
Accordions are a common name for collapsing regions of text within a web page, usually vertically.
The hypotenuse is the square root of the sum of the squares of the other two sides.
All triangles internal angles add up to 180 degrees.
They are commonly used to save vertical space on a web page, especially to contain information that is not really part of the main text. For example, definitions, asides or even spoiler information, such as a question with the answer hidden. As you can see, you're not limited in what you can put in them; formatted text, images, videos and anything else you can put on a Moodle page.