Graziano predicted that he would sell 420 tablecloths. He actually sold 520 tablecloths. What are the values of a and b in the table below?

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