To calculate the eccentricity of the ellipse defined by the equation x^2/49 + y^2/64 = 1, identify the values of a and b, where a^2 = 64 and b^2 = 49. The constant c is determined using the formula c^2 = a^2 - b^2, leading to c = √(64 - 49) = √15. The eccentricity is then calculated using the formula e = c/a, resulting in e = √15/8. For further clarification, online resources can provide additional formulas and explanations related to ellipse eccentricity.