Answer:
42 Units
Explanation:
Theorem
Tangent to a circle from the same point are equal.
Let the point of tangency be P,Q, R and S as labelled in the attached diagram.
By the above theorem,
BP=BQ=8 Units
AP=AS=4 Units
DS=DR=5 Units
CR=CQ=4 Units
Therefore:
AB=12 Units
BC=12 Units
CD=9 Units
AD=9 Units
Perimeter=12+12+9+9=42 Units