The triangle whose base is the coin image, and whose altitude is the cardboard-to-coin distance is similar to the larger triangle formed by the Sun's diameter and the Sun-to-Earth distance. The number of coins and Suns is the same. If you perform the experiment, you will find that the number of Suns that would fit between Earth’s surface and the Sun is approximately 110.
Work Step by Step
Please refer to Figure 1.6 on page 7 when you perform the experiment.