What does it mean 'what is the value' of a number

What describes horizontal cross section of the right rectangle 6m 8m 5m

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.

The pyramid below was dissected by a horizontal plane which shape describes the pyramid horizontal cross section