What is the equation for the problem, a store buys an item for $10 to earn a profit of $25 is what percent does the store need to markup the item

10 + 10x = 25
10x = 15
x =  1.5
x = 150%

10 * 1.5 = 15
10 + 15 = $25

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.