Question

The volume of a stack of identical circular drink coasters, each 1 centimeter thick, can be found using the function V(r)=8pi r^2 where r is the radius of a coaster. What does the constant 8 in the function represent?

Answer 1

The constant 8 represents the height of the stack and hence the number of coasters. (It represents the number of coasters.)

Explanation:

The formula for finding the volume of a cylinder is

V = πr²h

If you we take π =3.14 and h = 1 cm, as given in the question, then we can rewrite the formula for the volume of one coaster as

V = 3.14 * r²

But the formula in this question is

V(r) = 8*3.14 * r² so this means that there are 8 coasters here hence the formula for one coaster being multiplied by 8.