The middle angle B of triangle ABC is 2 times angle c and ah is perpendicular to BC and h, BM = cm, ab = 2hm

The middle angle B of triangle ABC is 2 times angle c and ah is perpendicular to BC and h, BM = cm, ab = 2hm

Do the bisector BD of ad ∥ BC intersection ∠ B to d
It can be concluded that ABCD is isosceles trapezoid and de ⊥ BC is equal to E
Then AB = ad = DC = he
M is the midpoint of BC me
So AB = 2hm
The concrete proof is very simple, you can reverse the corner by yourself

In the triangle ABC, ad bisector BAC, BD = CD

The intersection points of two perpendicular lines for AB and AC are e and f respectively. It can be proved that the triangle ade is equal to the triangle ADF, so AE = AF can be obtained. De = DF, de = DF and BD = CD can be obtained. The congruence of the right triangle BDE and the right triangle DCF can be obtained, so be = CF, because AB = AE + be, AC = AF + CF, so AB = AC

An isosceles triangle is an axisymmetric figure. Why is this sentence wrong?

It should be a straight line with the middle line on the bottom edge
The axis of symmetry is a straight line, and the middle line is a line segment