Final answer:
The circumferences of circle A and B are approximately 131.95 meters and 175.93 meters respectively, using the circumference formula C = 2πr. The relationship between a circle's radius and its circumference is constant for all circles, with the constant being 2π.
Step-by-step explanation:
To find the circumferences of Circle A and Circle B, we use the formula for the circumference of a circle, which is C = 2πr, where C is the circumference and r is the radius of the circle. The relationship between the radius of a circle and the circumference is constant and proportional across all circles. The constant of proportionality is 2π, which is approximately 6.283185.
For Circle A, with a radius (r) of 21 meters:
Circle A Circumference: C = 2π(21) = 2×(3.1415927...) × 21 ≈ 131.9469 meters
For Circle B, with a radius (r) of 28 meters:
Circle B Circumference: C = 2π(28) = 2×(3.1415927...) × 28 ≈ 175.9292 meters
The exact value would depend on the precision of π used, but in general, as the radius of a circle increases, the circumference increases proportionally. Therefore, the relationship between the radius and the circumference is indeed the same for all circles.