Is Mars wider than Earth in mean physical diameter?

Mars is often called Earth’s sister planet, and in pictures of the planets it can look much the same size. It is far smaller. Measured as a mean diameter, Mars is about 6,779 km across and Earth about 12,742 km, so Earth is nearly twice as wide, and Mars a little over half Earth’s width. The difference grows when you think in three dimensions. A world about 53% as wide as Earth has only about 28% of its surface area and about 15% of its volume, so it would take more than six planets the size of Mars to fill the space of one Earth. This duel compares width only, not mass, volume or how much of each surface is dry land. Mars is a small planet that looks bigger in our imagination than it is.