ErinWeeks
The area of a regular octagon is 35 cm2. What is the area of a regular octagon with sides five times as long?
A. 625 cm2
B. 875 cm2
C. 175 cm2
D. 245 cm2
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Hero
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Do you have the formulas for Area of a Polygon already?
ErinWeeks
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no i dont ! could you tell me the area
Hero
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\[A = \frac{Pa}{2}\]
ErinWeeks
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what is PA? what would i put there?
mathmate
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Hint: Area of similar polygons are proportional to the square of the linear dimensions (such as a side).
A polygon with a side 5 times as long has an area of 5^2=25 times the smaller polygon.
Hero
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^What he said
ErinWeeks
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so it would be B , 875 ?
mathmate
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Sounds good to me. :)
Hero
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I was just about to show her the long hard way of doing it.
Hero
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Nice intercept @mathmate
ErinWeeks
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thank you both !!
mathmate
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Sorry @Hero for butting in. I think the question was on the proportionality of figures.
mathmate
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yw! :)
Hero
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It was on Area of a Regular Polygon as well
mathmate
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It would definitely been beneficial to learn how to calculate the apothem and the length of the side given the area and number of sides. It would be a little long though.
Hero
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Yes, I know. I just said that it was the long way. Good job on saving time.
mathmate
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Sorry pal for this time. Hope that won't happen again! :)
Hero
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Okay bro