It is hard to type fractions here, but I will try. My book says I need to "tell why the ratio
$0.37 $1.85
______ and ______
1 stamp 5 stamps
is not a proportion."
It looks like a correct proportion to me!
Is the problem that there is a 1 as a denominator? Does the definition of "proportion" NOT allow 1 as a denominator?
To determine whether the given ratio is a proportion or not, we need to understand the definition of a proportion and check if it satisfies the criteria.
A proportion is an equation that states that two ratios are equivalent. In a proportion, the product of the means (the middle terms) is equal to the product of the extremes (the outer terms).
In this case, the given ratio is:
$0.37 $1.85
______ and ______
1 stamp 5 stamps
To check if it is a proportion, we need to compare the product of the means to the product of the extremes. In this case, the product of the means is $0.37 * 5 stamps = $1.85 stamps. The product of the extremes is $1.85 * 1 stamp = $1.85 stamps.
As you can see, the product of the means ($1.85 stamps) is indeed equal to the product of the extremes ($1.85 stamps). Therefore, the given ratio is indeed a proportion.
So, the problem you mentioned about having a 1 as the denominator is not correct. The definition of a proportion does not prohibit using 1 as a denominator. In fact, a proportion can have any value or numbers in its ratios; what matters is whether the product of the means is equal to the product of the extremes. In this case, it is true, so the ratio you provided is a valid proportion.