What expression represents the period of y=sin(kx) ?

How to solve it and what thw answer is

41/17 as a decimal rounded to the nearest hundredth

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex