-After one year, the interest accumulated, and the total in Sally’s account was $312. -After three years, the total was $340. After six years, the total was $380. - After nine years, the total was $430.
-After 12 years, the total amount in Sally’s savings account was $480.

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.