The angle between a plane P and the xy plane is , where 0 2 The projection of a rectangular region in P onto the xy plane is a rectangle whose sides have lengths x and y, as shown in the figure Prove that the area of the rectangular region in P is sec x y Area sec xy P Area in xy plane AxAy...

The angle between a plane P and the xy-plane is , where 0 < /2.

Question:

The angle between a plane P and the xy-plane is θ, where 0 ≤ θ < π/2. The projection of a rectangular region in P onto the xy-plane is a rectangle whose sides have lengths Δx and Δy, as shown in the figure. Prove that the area of the rectangular region in P is sec θ Δx Δy.