A polygon has rotational symmetry of 22.5 degrees. How many sides does the polygon have?

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81

Write an equation of the line that passes through 9,2 and is parallel to the line y=5/3x+9

Ateacher brought a pack of 17 batteries . each calculator uses 3 batteries . how many calculator can the teacher fill with batteries