Cynthia used 5 feet of lace to make 6 ribbons of the same size. Which statement BEST describes the amount of lace Cynthia used?

Try this explanation+solution:
1. According to the given graph it is possible to define A - amplitude and B - frequency of this function, then to substitute them to its equation.
2. A=5 (max. and min. values for vertical); B=2 (two periods in the length 2π).
3. y=5sin2x.