Hello, I am new to SW. I am trying to make a hemispherical cut (dip) on
a circular disk. I drew circle on the  disk and after trimming the top
portion of it, tried extruding. But the cut is not coming down through the
disk, rather it lies on the same plane. I tried drawing the circle in a plane
perpendicular to that of circular disk, but then the hemispherical disk is
lying on top of circular disk. I have attached the images.  Could anyone
suggest, what need to be done, inorder to get it cut through the disk?

Thanks in advance.