Does anyone know the answer to these? You just answer one or both oh, it's too confusing for me​

Mustafa contributes 11% of his $67,200 annual salary to his 401k plan. what is his pretax income

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.

The given diagram shows the parts of a right triangle with an altitude to the hypotenuse. using the two given  measures, find the other four.