My Math Forum [ASK] Two Cones

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 July 4th, 2018, 11:18 PM #1 Senior Member     Joined: Nov 2010 From: Indonesia Posts: 2,001 Thanks: 132 Math Focus: Trigonometry [ASK] Two Cones Azis wants to make two cones using cartons. The surface area of the first cone is twice the second. The side length of the first cone is also twice the second. Determine the ratio of those cones' radius! s1 = 2s2 L1 = 2L2 πr1(r1 + s1) = 2πr2(r2 + s2) r1(r1 + 2s2) = 2r2(r2 + s2) I was stuck with quadratic equations...
July 5th, 2018, 01:41 AM   #2
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 Originally Posted by Monox D. I-Fly Thanks to Denis McField who keeps calling me "Mr. Fly" ...
Are you related to Rufus T. Firefly?

July 5th, 2018, 04:48 PM   #3
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 Originally Posted by Maschke Are you related to Rufus T. Firefly?
I prefer D. Waterfly, though.

July 5th, 2018, 09:59 PM   #4
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 Originally Posted by Monox D. I-Fly I was stuck with quadratic equations...
It would seem that the surface area is intended to exclude the area of the base.

July 5th, 2018, 10:04 PM   #5
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 Originally Posted by skipjack It would seem that the surface area is intended to exclude the area of the base.
But in my language it said "luas permukaan", and it strictly include the base area. Otherwise they would use the phrase "luas selimut" (side area) instead.

 July 6th, 2018, 12:15 AM #6 Global Moderator   Joined: Dec 2006 Posts: 20,464 Thanks: 2038 According to Google's translator, "luas permukaan" means "surface area" (as distinct from "total surface area"). Although a more specific phrase is available, it's possible that the need for it was overlooked.

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