A line passing through which of the following pairs of coordinates represents a proportional relationship? A.
(1, 3) and (3, 6)
B.
(1, 1) and (1, 3)
C.
(1, 2) and (2, 3)
D.
(1, 3) and (2, 6)

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.