So I have this square and theres a circle inside of it. The circle of radius $r$ is inscribed in the square. So how do I find the area of the square in terms of $r$? I know that area of a circle is $\pi r^2$, but they wouldn't give me the area of the parts of the square the circle doesn't cover. any help?
Area of a square using circle
1
$\begingroup$
algebra-precalculus
circles
1 Answers
5
Hint: Think about the relationship between the radius of the circle, the diameter of the circle, and the side length of the square.
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Do you know the area of a square given its side length?
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0ok, if im getting somewhere, the radius of the circle is half the length of one side of the square, and the area of the square is s^2, so, in terms of r, would it be 2r^2? – 2011-09-20
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0@Ronnie: Close, but not quite. The side length $s$ of the square is equal to $2r$, but $$\text{area of square} = s^2=(2r)^2=(2\times r)\times (2\times r)=4\times r\times r = 4r^2$$ not $2r^2$. – 2011-09-20
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0yea i meant (2r)^2 sorry lol – 2011-09-20
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0@Ronnie: Ah, ok :) If my answer has been helpful, you can upvote it (by clicking on the little "up arrow" on the upper left of my answer, above the number) or accept it (by clicking the green check mark a little below that), if you would like. – 2011-09-20
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0done and done. Theres another question i need help with. I have 3000 feet of fencing, and im suppose to find the area of the rectangle with x as the length. I did A=x*(3000-2x). Now it asks to find for what value of x is the area largest, and im stuck as to what to do? – 2011-09-20
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0@Ronnie: You should ask that as a separate question :) – 2011-09-20
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0And by the way, I should just mention that it is considered polite on this site to upvote and accept answers that you have found helpful; I recommend going back over your older questions and doing so. – 2011-09-20
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0oh i know its just that i forgot since last time it didn't let me (i think my level was too low or something) and i found the answer after realizing it was right on my face (like this one lol) thanks for the feedback tho, it was great help – 2011-09-20