Answer: 8: 21
Step-by-step explanation:
Given : An architect builds a model of a park in the shape of a rectangle. The length of the model = 40.64 centimeters
The width of the model = 66.04 centimeters
Since,
.
Then , 
Now, the length of the model = 
The width of the model = 
Sum of length and width = 16+26=42 inches
Now, the ratio of the length to the sum of the length and width in inches :_
Hence, the ratio of the length to the sum of the length and width in inches in simplest form = 8:21