Please help

What is the volume of a rectangular prism if the length is 10.4 mm the width is 5 mm in the height is 8 mm

Given: m∠ adb = m∠cdb ad ≅ dc prove: m∠ bac = m∠bca lol

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.