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Ledah
 3 years ago
Two regular decagons have areas of 30 mm² and x² + 7x mm². What values of x make the decagons congruent?
Ledah
 3 years ago
Two regular decagons have areas of 30 mm² and x² + 7x mm². What values of x make the decagons congruent?

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apoorvk
 3 years ago
Best ResponseYou've already chosen the best response.1Since the areas are equal, equate the expressions for both areas: \[30 = x^2 + 7x\] Now, bring every term to the same side, and lo! you have a quadratic. solve it, find 'x' and enjoy!

FoolAroundMath
 3 years ago
Best ResponseYou've already chosen the best response.1Two polygons are congruent if they are exactly the same. What can you say about the area of two congruent polygons?

Ledah
 3 years ago
Best ResponseYou've already chosen the best response.0They should also be the same

FoolAroundMath
 3 years ago
Best ResponseYou've already chosen the best response.1So, all you have to do is equate their areas and get a quadratic equation as obtained by @apoorvk and solve it.

Ledah
 3 years ago
Best ResponseYou've already chosen the best response.0I got 5 and 6 as an answer.. I'm not sure if its right I'm still checking my work

apoorvk
 3 years ago
Best ResponseYou've already chosen the best response.1Umm, sorry that isn't correct  did you split the middle term and factorize it?

FoolAroundMath
 3 years ago
Best ResponseYou've already chosen the best response.1\(x=5\) does not satisfy the equation. What you have is \(x^{2}+7x30 = 0\) Can you factorise the left hand side?
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