Which expression is not equal to 28? A. ( 9 + 25 ÷ 5 ) × 2
B. [ ( 13 − 4 × 2 ) − 1 ] × 7
C. 42 ÷ 6 + 28 ÷ 4
D. 7 × [ 8 − ( 12 − 4 × 2 ) ]

Hello!
volume of sphere =4/3.pi.r^3

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.