1. In the triangle ABC, the angle ABC=90 degrees, m is a point above AB, AM=BC, N is a point above BC, CN=BM, and even an and CM intersect at point P. Sorry, I won't draw on the Internet. 2. In quadrilateral ABCD, AB=BC, angle ABC=60 degrees, P. Prove that PA+PD+PC is greater than or equal to BD3 and triangle ABC, where AB=AC, D is a point above BC, E is a point above AD, and horn bed = angle BAC= twice angle CED. It is proved that CD4 and ABC with BD= twice are isosceles triangles with angle B= angle C=40 degrees. Expand AB to d to verify AD=BC and angle BCD. The angle ACB=80 degrees, O is a point in the triangle, the angle OAB= 10 degrees, and the angle OBA=30 degrees. Find the length of the line segment AO. 6. In triangle ABC, angle BAC=80 degrees, angle ABC=60 degrees, D is a point inside the triangle, angle DAB= 10 degrees, and angle DBA=20 degrees.