Question

Don't understand the measure

Answer 1

Hello,

$\widehat{ABD}=\frac{180-40}{2}$=70 (sum of angles of a triangle=180°)

$\widehat{ABE}=180-70=110$ supplementary angles

$\widehat{ABE}=\widehat{DCF}$ translation BC

$\widehat{BCF}=110-40=70$ image of the angle DAB by the axis symmetry DB

$\widehat{BCF}=\widehat{BEF}$ opposed angles of a parallelogram
are supplementary.

$\widehat{BEF}=\widehat{HEG}$ opposed angles by the vertex

$\widehat{HEG}=\widehat{IHE}=70$ alterne-interne angles (sorry for the words English is difficult for me)