(1) proves that triangle BOD and triangle COE are congruent.

(2) Prove that triangle AOD and triangle AOE are congruent.

A method to prove the coincidence of triangle BOD and triangle COE;

ASA (Angle and Angle), that is, two angles of a triangle are equal, and the sides of two corner clips are equal to two triangles.

It is proved that in triangle BOD, if CD is perpendicular to AB, then the angle ODB = 90,

In the triangle COE, BE is perpendicular to AC, then the angle OEC = 90°,

Angle DOB and angle EOC are diagonal, then angle DOB= angle EOC,

Extrapolation angle B= angle c

Because angle B= angle c, OB=OC and angle DOB= angle EOC,

So the BOD of the triangle and the COE of the triangle are congruent.

You can get OD=OE.

A method to prove congruence between triangle AOD and triangle AOE;

HL (hypotenuse, right angle side) refers to the congruence of hypotenuse and right angle side in a right triangle.

It is proved that in triangle AOD, if CD is perpendicular to AB, then the angle ODA = 90,

In the triangle AOE, perpendicular to AC, then the angle OEA = 90,

Because AO=AO, OD=OE, and the congruence of triangle AOD and triangle AOE is obtained.

So the angle 1= angle 2.