Question

Which of these pairs of quantities are proportional to each other? If the quantities are proportional, determine the constant of proportionality. If the quantities are not proportional, select the 'not proportional' option.

1) radius and diameter of a circle
2) radius and circumference of a circle
3) radius and area of a circle
4) diameter and circumference of a circle
5) diameter and area of a circle

Answer 1

The pairs of quantities that are proportional to each other in a circle are radius and circumference, with a constant of proportionality of 2π.

Step-by-step explanation:

The pairs of quantities that are proportional to each other in a circle are:

1. Not proportional: radius and diameter of a circle
2. Proportional: radius and circumference of a circle (with the constant of proportionality being 2π)
3. Not proportional: radius and area of a circle
4. Not proportional: diameter and circumference of a circle
5. Not proportional: diameter and area of a circle

Therefore, only the pair of radius and circumference of a circle are proportional, with a constant of proportionality of 2π.