Which one from among the following planets is largest in size ?

Among the four terrestrial or inner planets—Mercury, Venus, Earth, and Mars—Earth is the largest in size [1][3]. Earth has a mean diameter of approximately 12,756 km, making it the largest terrestrial planet in the Solar System. Venus is often referred to as 'Earth's twin' due to its similar size, mass, and density, but it is slightly smaller with a diameter of about 12,104 km [2]. Mars is significantly smaller, with a diameter of 6,792 km, which is roughly 53% of Earth's diameter [2]. Mercury is the smallest of the four, with a diameter of approximately 4,879 km. Consequently, Earth has the largest volume and mass among the options provided [2].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 2: The Solar System > Inner Planets > p. 27
2. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 13: Our Home: Earth, a Unique Life Sustaining Planet > 13.2 What Do the Planets of Our Solar System Look Like? > p. 213
3. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > The Solar System > p. 2