The sum of the measures of angles in all quadrangles is 360 °. Therefore:
[tex](25x+1)+(25x-2)+(20x-1)+82=360\\\\70x+80=360\ \ \ |-80\\\\70x=280\ \ \ |:70\\\\x=4[/tex]
[tex]m\angle D=(20x-1)^o\to m\angle D=(20\cdot4-1)^o=79^o\\\\Answer:\ B.\ 79^o[/tex]
