PSAT Math : How to find the ratio of diameter and circumference

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : Diameter And Chords

Let  represent the area of a circle and  represent its circumference. Which of the following equations expresses  in terms of

Possible Answers:

Correct answer:


The formula for the area of a circle is , and the formula for circumference is . If we solve for C in terms of r, we get

We can then substitute this value of r into the formula for the area:


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