Question

ABC is a triangle in which DE || BC. find angle A​

Answer 1

In Triangle BEC

Angle(E+B+C)=180° {Angle sum property}

Angle C=70°

Angle BDE+Angle DBC = 180 (Co-Interior angles)

105° + Angle DBE + 30° =180°

Angle DBE=45°

Angle ABC=75° or Angle B=75°

Now in Triangle ABC

Angle (A+B+C)=180° {Angle sum property}

Angle A+75°+70°=180°

Angle A=35°