Which list contains three equivalent fractions for 2/5
a-4/10, 6/20, 10/25.
b- 4/10, 6/15, 8/20
c- 6/15, 8/16, 10/25
d- 6/15, 8/20, 12/25

How many groups are there?

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.