5.3.1.8 Construction of secrets

Condition: Point \ (O \) and \ (\ MATHRM {O} {1} \)-facial centers \ (A b c d \) and \ (A_ {1} B_} C_ {1} D_ {1} EC) Cuba \ (A B C D A_} B_ {1} C_ LUA D_ {1} \). On the segment \ (o_ {1} \) the point \ (s \) is taken so that \ (o_ {1} s: o s = 1: 3 \). Through this point, a cross -section of the cube was drawn, parallel to its diagonal \ (a c_ {1} \) and diagonal \ (b d \) base. Find the cross -sectional area if the length of the cube rib is \ (A \).