Which equation correctly shows the multiplication of the means and extremes in the proportion 7.2 ∕ 9.6 = 21.6 ∕ 28.8?
a. 7.2 ⋅ 9.6 = 21.6 ⋅ 28.8
b. 9.6 ⋅ 21.6 = 28.8 ⋅ 7.2
c. 7.2 ⋅ 21.6 = 28.8 ⋅ 9.6
d. 7.2 ⋅ 28.8 = 21.6 ⋅ 28.8
Answer:
b. 9.6 ⋅ 21.6 = 28.8 ⋅ 7.2
Step-by-step explanation:
When a proportion say a/b = c/d is given, the outer terms are called the extremes while the inner/middle terms are called the means.
In the case of a / b = c / d,
the outer terms are a and d
the inner terms are b and c
Often times, we find the cross products of the proportion to test whether the two ratios in the proportion are equal. To do that, we find the product of the extremes and equate it to the product of the means.
In the case of a / b = c / d,
the cross products are a x d and b x c
So if a x d = b x c, then a/b = c/d is a true proportion.
Now to the question;
Given proportion: 7.2 / 9.6 = 21.6 / 28.8
Extremes = 7.2 and 28.8
Means = 9.6 and 21.6
The correct multiplication of the means and extremes is therefore
9.6 x 21.6 = 7.2 x 28.8
or
9.6 · 21.6 = 7.2 · 28.8
