Final answer:
The ratio of a circle's diameter to its circumference is 1:π, where π (pi) is the mathematical constant approximately equal to 3.14159. This comes from the formula C = πD, indicating that the circumference is pi times the diameter.
Step-by-step explanation:
The question asks about the ratio of a circle's diameter to its circumference. According to the mathematical constant π (pi), which is the ratio of a circle's circumference to its diameter. The value of pi is approximately 3.14159, which means that for every diameter length, the circumference of the circle is approximately 3.14159 times larger. Therefore, the correct answer to the ratio of a circle's diameter to its circumference is 1:π.
This understanding is based on the formula C = 2πr, where C represents the circumference and r represents the radius of the circle. The diameter, represented by D, is twice the radius (D = 2r), leading to the circumference formula also being expressed as C = πD, which directly gives us the ratio of diameter to circumference as 1:π.