Question

Let f be the function that determines the area of a circle (in square cm) that has a radius of r cm. That is, f ( r ) represents the area of a circle (in square cm) that has a radius of r cm. Use function notation to respond to each item below. Represent the area (in square cm) of a circle that has a radius of 4.3 cm.

Answer 1

Answer:

$f(r)=\pi.r^2\\f(4.3)=58.09\ cm^2$

Explanation:

Functions

When one magnitude depends on other (or others), we usually try to express them as a function which can contain any number of variables, constants, and operations.

The area of a circle is computed by the well-known formula

$A=\pi r^2$

We are required to use function notation to express the area of a circle f(r) in terms of the radius r. If the radius is in cm, then the area is in $cm^2$.

The required function is

$f(r)=\pi r^2$

For a radius of 4.3 cm:

$f(4.3)=\pi\times 4.3^2=58.09\ cm^2$

$\boxed{f(4.3)=58.09\ cm^2}$