Hint: In this question, the object is to determine the number of edges that the kaleidoscope has. In case of geometry the edge is a line segment that joins the two vertices in a polygon or any high dimensional shape. In case of the polygon the edge is the line segment of any shape is generally called side. The kaleidoscope is made of rectangles that have four sides and the two triangles that have three sides each.
Complete Step By Step solution: As we know that the kaleidoscope is made up of three rectangles and two triangles that are joined together. Let us consider the figure for the kaleidoscope as shown below.
As we know the base is generally a rectangle, the other two rectangles share a common side with the base rectangle and the two rectangles have the base which are the other two remaining sides of the base rectangle.
Thus, the total number of edges is the total number of sides that the kaleidoscope has and these are two as seen from the figure.
Note: As we know that the kaleidoscope is generally an optical instrument that has two or more reflecting surfaces and are connected to each other at an angle such that objects that are at one of the ends of the mirror, appear as multiple patterns when the object is viewed from the other end. The multiple patterns appear due to reflection of the objects inside the kaleidoscope mirror that are attached at tilted angle.