The next row, for the cosine, is just the sine’s row in reverse order.

This happens because you have the angles and their complements in reverse order, too.

The next row is for the tangent. In a right triangle, you find the tangent of an acute angle with the ratio opposite/adjacent. You get the same ratio when you divide sine by cosine.

Because you already know the values for sine and cosine, you can use this property (tangent equals sine divided by cosine) to get the tangent values for the table.

The table shows the completed table with the tangent row.