PSAT数学:如何找到直径和的比值circumference

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 :Diameter

Letrepresent the area of a circle andrepresent its circumference. Which of the following equations expressesin terms of?

Possible Answers:


Correct answer:

Explanation:

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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