128, 134, 140, 146, 152,, what's the next number if the pattern continues

158 would be the next one if my theory is correct it goes

+6+6+6+6+6+6

The next number is 158. 
134-128=6
140-134=6
146-140=6
152-146=6
We see that the distance between all of the numbers is 6, so we add 6 to 152. Therefore, we get 158

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.