Write each formula as an English phrase using the word varies or ...

Question

Write each formula as an English phrase using the word varies or proportional. 
C=2πr, where C is the circumference of a circle of radius r.

Accepted Answer

Hey, everyone here we are given for the following formula use the term varies or proportional to write them as word statements here. The formula is L is equal to pi times W where L is the perimeter and W is the width of any curve having constant width. Here we have four answer choice options. Answer A, the width of a curve varies directly with pi answer B, the perimeter of A curve varies inversely with pi answer choice C, the perimeter of a curve is inversely proportional to its width and answer D the perimeter of a curve is directly proportional to its width. So looking at our formula again, we have L is equal to pi times W. Well, here we see we have a constant pi just multiplied by the variable W. And so this tells us that L is directly proportional to W again because it is simply multiplied by some constant. So in other words, using what we know about our variables, we have the perimeter of a curve varies directly with its width. Or in other words, as answer choice D states, the perimeter of a curve is directly proportional to its width. So here we are left with answer choice D again, the perimeter of a curve is directly proportional to its width or that it varies directly as its width. Thanks for watching. I hope you found this video helpful and I'll see you again next time.

Write each formula as an English phrase using the word varies or proportional. C=2πr, where C is the circumference of a circle of radius r.

Key Concepts

Circumference of a Circle

Direct Variation

Proportional Relationships

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