Final answer:
The appropriate unit of measure for the weight of a letter is ounces (oz), which allows for accurate and manageable figures for lightweight objects.
Step-by-step explanation:
When choosing an appropriate unit of measure for the weight of a letter, we need to consider the general weight range of such an item. Letters are typically lightweight and require a unit of weight that can measure small quantities accurately. The customary units of weight are ounces (oz), pounds (lb), and tons, with ounces being the smallest unit. For objects with very light weight, like letters, ounces are the most suitable unit of measure, as a letter's weight can vary from light to just a few ounces depending on the thickness and size.
In the case of Jesse in the mailroom, he chose kilograms to weigh a box of books and documents, a unit that's appropriate for heavier objects. However, for the weight of a letter, we would use ounces, which allows for precise measurement of lighter items. The weight of a pencil, which is more than a paperclip but less than a kitten, would be best measured in grams in metric units, showing how different units suit different weights. When measuring the weight of smaller and lighter objects, such as letters, using ounces ensures a manageable and understandable figure that accurately reflects the object's weight.