The total area of all the windows and doors was calculated as 26.4m squared. What is the area of the walls only?

Which expression gives the area of the triangle shown below

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.

How do i do this activity, is appreciated