As shown in the figure, ad and be are the heights of BC and AC respectively in ABC
Because △ ACD and △ BCE are right triangles, ∠ C + ∠ CAD = ∠ C + ∠ CBE = 90, so ∠ DAC = ∠ EBC
Because △ ACD and △ BCE are right triangles, ∠ C + ∠ CAD = ∠ C + ∠ CBE = 90, so ∠ DAC = ∠ EBC