Answer:
m∠ D = 110°.
Justification is below.
Step-by-step explanation:
Consider quadrilateral CDEF as a parallelogram,
Opposite sides of a parallelogram are parallel
∴ DE || CF
If two lines are parallel then the interior angles SUM is 180°
Angle C and Angle D are interior angles.
∴ m ∠C + m∠ D = 180°
Here
m ∠C = 70° {Given}
on substituting the above value we get
∴ 70 + m∠ D = 180°
∴ m∠ D = 180 - 70
∴ m∠ D = 110°
∴ m∠ D = 110° which is the required answer.
