Final answer:
The parabola of y = 3x^2 is 'skinnier' than that of y = x^2 because the larger coefficient of x^2 in the equation causes the graph of the parabola to rise more quickly, thus appearing narrower.
Step-by-step explanation:
When comparing the shapes of the parabolas of y = x^2 and y = 3x^2, we are looking at how the coefficient of x^2 affects the width of the parabola. For the equation y = x^2, the coefficient is 1, which gives it a certain width. However, when looking at the equation y = 3x^2, the coefficient is larger - it is 3.
This larger coefficient causes the parabola to be 'skinnier.' The reason is that for any given value of x, the value of y is tripled compared to the y = x^2 parabola, which means the graph will rise more quickly and thus appear narrower. Therefore, the correct answer is A: The parabola of y = 3x^2 is skinnier because it has a larger coefficient of x^2.