Answer:
The ratio of the length of the semi-major axis to the distance between the focus and the center is known as the eccentricity of an ellipse.
Since the center and focus of a circle coincide, its eccentricity is zero.
Since the focus and center are closer than the semi-major axis, an ellipse’s eccentricity is less than 1.
Since the distance between the focus and the vertex is equal to the semi-major axis, a parabola’s eccentricity is 1.
Since the focus and center are farther apart than the semi-major axis, a hyperbola’s eccentricity is greater than 1.
The eccentricity of the earth, an oblate spheroid (a kind of ellipse), is less than 1. Consequently, (a) Less than 1 is the right choice.
Answer:
The ratio of the length of the semi-major axis to the distance between the focus and the center is known as the eccentricity of an ellipse.
Since the center and focus of a circle coincide, its eccentricity is zero.
Since the focus and center are closer than the semi-major axis, an ellipse’s eccentricity is less than 1.
Since the distance between the focus and the vertex is equal to the semi-major axis, a parabola’s eccentricity is 1.
Since the focus and center are farther apart than the semi-major axis, a hyperbola’s eccentricity is greater than 1.
The eccentricity of the earth, an oblate spheroid (a kind of ellipse), is less than 1. Consequently, (a) Less than 1 is the right choice.