Let's use the given information to find the length of a side of the stained-glass window.
Step 1: Define the variables
Let s represent the length of a side of the rhombus.
Step 2: Set up the equation using the given information
The perimeter of the rhombus is 7 times the length of a side, decreased by 27. Since a rhombus has 4 equal sides, we can set up the equation as follows:
Perimeter = 4s
7s - 27 = 4s
Step 3: Solve for the length of a side (s)
Subtract 4s from both sides of the equation:
3s = 27
Now, divide both sides by 3:
s = 9
So, the length of the side of the stained-glass window in the shape of a rhombus is 9 meters.