2, 1, 1/2, 1/4 which number should come next​

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex

Round to the nearest ten thousandth. i dont get this