Here we have , building engineer analyzes a concrete column with a circular cross section. The circumference of the column is 18π, pi meters. We need to find What is the area A of the cross section of the column .Let's find out:

We know that , Circumference of circle = $2\pi r$

⇒ $Circumference = 2\pi r$

⇒ $18\pi= 2\pi r$

⇒ $\frac{18\pi}{2\pi }= \frac{2\pi r}{2\pi }$

⇒ $\frac{18\pi}{2\pi }=r$

⇒ $r=9$

We know that area of circle = $\pi r^2$

⇒ $Area= \pi r^2$

⇒ $Area= \pi 9^2$

⇒ $Area= 81\pi$

Therefore , the area A of the cross section of the column is $(81\pi )m^2$ .

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Which statement is true about the meaning of the equation

timurjin [86]

An equation says that two things are equal. It will have an equals sign (assuming you know what that is) like this:
7+2=10-1
What the equal says on the left, is equal to the answer on the right.
Basically, it's a statement saying "equals that"

I don't fully understand your question, but I hope it helped you at least a little.

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Well...their relations but not functions

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