Question

Consider five circles with a radii of 1, 2, 4, 8, and 16 inches. Write your answer in terms of pi r square. Compare the areas and circumference of a circle when you double the radius? What happens to the area?  What happens when you triple the radius.
      The table lists the radius, circumference and area.

Answer 1

When you change the radius (multiply by k), a 1D size, the circumference is multiplied by k (1D), while the area is multiplied by $k^2$ (2D). I hope this helps on this problem and others.