Answer:
0.00736 Sq. Yard size of decagon is used
Explanation:
Given
Each side of Decagon 
 centimeter
 centimeter
Area of Decagon 

Here a is the side of decagon
Substituting the given values, we get - 
 Square centimeter
Square centimeter
1 square centimeter = 0.000119599 square yard
Area in yard = 0.00736 Sq. Yard