61. In a regular truncated quadrilateral pyramid, a section is made through the diagonals of the bases and a section passing through the side of the lower base and the opposite side of the upper base. The angle between the cutting planes is $\alpha$. Find the ratio of the areas of the sections.
61. The area of the projection of the second section onto the first plane is half the area of the first section. On the other hand (see problem 8), the ratio of the area of the projection of the second section to the area of the section itself is $\cos \alpha$.

Answer: $2 \cos \alpha$.