Answer:
A. y = 3x
Step-by-step explanation:
A proportional relationship is described by an equation of the form ...
y = kx
The equation of answer choice A is in that form with k=3. It describes the relationship as proportional.
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Answer choice B gives a single point on the position versus time graph. There is nothing to indicate it is part of a proportional relation.
Answer choice C tells you the relationship between time and distance (speed) is not constant. That assures you the relationship is NOT proportional.
Answer choice D does not tell you that the time starts counting when the turtle starts at the rock. It tells you the relation is linear, but does not tell you the relation is proportional.
