A proportion looks like this:

It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion

And then solve it for x:

15. 12, 8, 14, 7, 16, 6, 18, .......,<br>b. 6, 20<br>a. 5, 18<br>d.6,21<br>C. 5, 20
babymother [125]
Answer:
What is the question. Please rewrite the question.
Answer:
i think a
Step-by-step explanation:
From the above definition, we can say that the cross-section, as a result of the plane intersecting the sphere through its centre, will be a circle with the radius "r" same as that of the given sphere. Thus, the area of the cross section is 15.2 m²