Final answer:
The relationship between the length of tangent CD and secant ED of a circle, as given, is CD = 7ED. Therefore, the correct answer is a) CD = 7ED, which is a direct relationship provided in the question itself.
Step-by-step explanation:
The question is asking to find the relationship between the lengths of a tangent (CD) and a secant (ED) of a circle, given that CD = 7ED according to the problem statement. This is a geometry problem involving properties of circles, tangents, and secants.
In this geometry problem, we can apply rules that relate tangents and secants to a circle. In particular, for a circle with a tangent CD and a secant line extending from F, passing through point E, and continuing to point D, you can use the equation CD2 = ED * FD.
However, it's worth noting that the given information already states that CD = 7ED. Therefore, no calculations need to be performed, and this direct relationship answers the question. The correct answer is option a) CD = 7ED, which agrees with the information given in the problem statement.