Answer: 20.8 cm
<u>Step-by-step explanation:</u>
Notice that the corners of the squares form a line.
Set the x-axis to time and the y-axis to length of a side (not perimeter) to create coordinates.
At 0 seconds the side length is 1 --> (0, 1)
At 2.5 seconds the perimeter is 32 (side length is 32/4 = 8) --> (2.5, 8)
First, find the slope between the coordinates using
Let (x₁, y₁) = (0, 1) and (x₂, y₂) = (2.5, 8)
Next, use the Point-Slope formula to find the equation of the line:
Lastly, find the side length (y) when x = 1.5
y = 2.8(1.5)x + 1
= 4.2 + 1
= 5.2
Perimeter of a square = 4 times the side length
P = 4(5.2)
= 20.8