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Thread: [ASK] Two Cones

  1. #1
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    [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...
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  2. #2
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    Re: [ASK] Two Cones

    The area of any object is proportional to the product of two lengths. Taking r1 and s1 to be the radius and side length of the first cone area1= kr1s1. For the second object, let r2 and s2= 2s1 be the radius and side length. area2= 2area1= k(2s1)r2. 2kr1s1= 2kr2s2. s2= s1.
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  3. #3
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    Re: [ASK] Two Cones

    What is that k?
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  4. #4
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    Re: [ASK] Two Cones

    Quote Originally Posted by HallsofIvy View Post
    The area of any object is proportional to the product of two lengths. Taking r1 and s1 to be the radius and side length of the first cone area1= kr1s1. For the second object, let r2 and s2= 2s1 be the radius and side length. area2= 2area1= k(2s1)r2. 2kr1s1= 2kr2s2. s2= s1.
    Can you explain the underline text (?!)
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