In △ ABC, be is the middle line, ad ⊥ BC is in D, ∠ CBE = 30 °, please prove: ad = be The figure can be drawn according to the title. There are three sides of the triangle, one middle line and one high line. There are five sides in total
EH is perpendicular to BC through E and BC is perpendicular to h through E,
AE=CE;
AD⊥BC;
EH⊥BC
So eh / / AD is the median of △ ACD;
EH=1/2AD;
In the right triangle beh, ∠ CBE = 30;
So eh = 1 / 2be;
So: ad = be;