To determine the length a pendulum has traveled with an amplitude of 10.0 m and 7 vibrations, one must first understand the relationship between amplitude, frequency, and the total distance traveled. The total distance can be calculated by considering that the pendulum travels a distance equal to twice the amplitude for each complete vibration. Therefore, for 7 vibrations, the total distance would be 7 vibrations multiplied by 2 times the amplitude. Assumptions may include treating the pendulum's motion as simple harmonic motion and neglecting factors like air resistance. The final calculation yields a total distance traveled of 140.0 m.