Final answer:
The largest volcano on Mars, Olympus Mons, is three times higher than the tallest mountain on Earth as measured from their bases.
Step-by-step explanation:
The largest volcano on Mars, Olympus Mons, is three times higher than the tallest mountain on Earth as measured from their bases. Olympus Mons has a height of more than 20 kilometers, which is almost three times the height of Mount Everest, the tallest mountain on Earth. This information is based on various sources that compare the heights of mountains on different planets.