The cost to mail a letter that is 3.48 ounces is 
Further explanation:
The piecewise defined function is defined as a function that takes different values in different interval. It is defined on the sequence of intervals.
Given:
The price to mail a weight not over 1 ounce is 
The price to mail a weight not over 2 ounce is 
The price to mail a weight not over 3 ounce is 
The price to mail a weight not over 3.5 oounce is 
Explanation:
If the weight of the letter is less than or equal to one ounce then the cost is 
Then function can be expressed as follows,

If the weight of the letter is greater than 1 ounce and less than or equal to 2 ounce then the cost is 
Then function can be expressed as follows,

If the weight of the letter is greater than 2 ounce and less than or equal to 3 ounce then the cost is 
Then function can be expressed as follows,

If the weight of the letter is greater than 3 ounce and less than or equal to 3.5 ounce then the cost is 
Then function can be expressed as follows,

The piecewise defined function can be expressed as follows,

The cost to mail a letter that is 3.48 ounces is 
Learn more:
1. Learn more about inverse of the functionhttps://brainly.com/question/1632445.
2. Learn more about equation of circle brainly.com/question/1506955.
3. Learn more about range and domain of the function brainly.com/question/3412497
Answer details:
Grade: High School
Subject: Mathematics
Chapter: Linear Equation
Keywords: solving equation, recent year, the rate of first class postage, weight, piecewise-defined function, cost to mail a letter, price, model, ounce.