Answer:
-   
- Dimensions of the flag: 
        
- Area of the flag:  
 
Step-by-step explanation:
 <em><u>The missing figure of the exercise is attached.</u></em>
<em><u /></em>
 We know that the perimeter of the triangle is given by:
 
 Where "s" is the side lenght of the triangle.
 Solving for "s", we get:
 
 
 Therefore, if the perimeter of the triangle is 126 inches, its side length is:
 
  Since   , we know that "s" in feet is:
, we know that "s" in feet is:
 
 The area of a rectangle can be calculated with this formula:
 
 Where "l" is the lenght and "w" is the width
 
 We can observe in the figure that the lenght and the width of the flag are:
 
 Then, the dimensions of the flag are:
 
 And the area is:
 