The equatorial radius of the Earth refers to the distance from the center of the Earth to the equator. In this question, we are asked to estimate the value of the equatorial radius.

Option 1 states that the equatorial radius of the Earth is approximately 6380 km. This means that if we were to measure the distance from the center of the Earth to the equator, it would be around 6380 km.

Option 2 suggests that the equatorial radius is approximately 6740 km.

Option 3 proposes a value of 7380 km for the equatorial radius.

Option 4 states that the equatorial radius is approximately 7740 km.

Out of these options, the correct answer is Option 1, which estimates the equatorial radius of the Earth to be around 6380 km.