d = 97°
Explanation:
a and 79° are a linear pair and sum to 180° , then
a + 79° = 180° ( subtract 79° from both sides )
a = 101°
b and 79° are corresponding angles and are congruent , then
b = 79°
c and 83° are vertically opposite angles and are congruent , then
c = 83°
d and c are same- side interior angles and sum to 180° , then
c + d = 180° , that is
83° + d = 180° ( subtract 83° from both sides )
d = 97°