Answer:
d = 90° , e = 71° , f = 109°
Explanation:
d and the right angle are a linear pair and sum to 180°
d + 90° = 180° ( subtract 90° from both sides )
d = 90°
e and 71° are vertically opposite angles and are congruent , then
e = 71°
e and f are a linear pair and sum to 180°
e + f = 180° , that is
71° + f = 180° ( subtract 71° from both sides )
f = 109°