Question

Answer 1

Ta có: 

Xét tứ giác ABCD là hình thang vuông có đáy AD, BC:

=>\(\widehat{A}+\widehat{B}+\widehat{C}+\widehat{D}=360^o\)

\(\Leftrightarrow\widehat{D}=360^o-\widehat{B}-\widehat{C}-\widehat{A}\)

\(\Leftrightarrow\widehat{D}=360^o-90^o-90^o-69^o=111^o\)

Vậy \(\widehat{ADC}=111^o\)

 

Answer 2

Ta có: 

\(\widehat{ADC}=360^0-\left(\widehat{A}+\widehat{B}+\widehat{C}\right)\)

\(\widehat{ADC}=360^0-\left(90^0+90^0+69^0\right)\)

\(\widehat{ADC}=111^0\)

 

Answer 3

90 độ