Answer:
Base of each parallelogram is
The area of the smallest rectangle of wall that the mirror could fit on 
Step-by-step explanation:
Given : The parallelograms have a combined area of 9 1/3 square yards. The height of each parallelogram is 1 1/3 yards.
To Find:a) how long is the base of each parallelogram? b) what is the area of the smallest rectangle of wall that the mirror could fit on?
Solution :
Since The parallelograms have a combined area of 9 1/3 square yards = 
Since this is the area of two combined congruent parallelograms
So, area of each parallelogram =
Thus area of each parallelogram is 
To Calculate base of each parallelogram
Formula of area of parallelogram = Base * Height
Since height of each parallelogram is 
Thus 




hence the base of each parallelogram is
b) we can assume that the two parallelograms form a rectangle.
So, in this case length will increase since two parallelograms are combines so length of the resultant will be twice the length of each parallelogram
area of a rectangle is length times width.
length is 3 1/2 yards * 2 = 7 yards
width is 3 1/2 yards
Area of rectangle = 7 yards * 3 1/2 yards
Area = 7 yd * 7/2 yd
Area = 7*7 / 2 yd²
Area = 49 / 2 yd²
Area = 
The area of the smallest rectangle of wall that the mirror could fit on 