Which statement correctly identifies the line of reflection?

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Look at triangle wxy what is the length (in centimeters) of the side wy of the triangle?