I don't believe that 1 and 17/20 can be simplified any further. It is already in lowest terms.
Answer: 
Step-by-step explanation:
Let the angle ADC = x degree
Since, By the given diagram, In triangle BDC,

⇒ 
⇒ 
⇒ 
Now, In triangle ADC,

⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
Step-by-step explanation:
Area of shaded region = area of exterior rectangle - area of interior rectangle

Answer:
9/10 or 0.9
Step-by-step explanation:
Your answer is 3
YOU are welcome