Geometry: An Interactive Journey to Mastery

(Greg DeLong) #1
G௘ͽ îͼ௘௘ͽ^3 = 27.
H௘ͽ ©¹ ̈ ̧§· 121 3 |
I௘ͽ $UHD î IW^2  î LQ^2.
Number of tiles | 25   tiles.
 &RVW î 
J௘ͽ ͼ௘௘ͽ^2  FP^2.
K௘ͽ V 1  ͼ௘௘ͽ^3 in^3 and V 2 = 800 in^3. So, k^3 = 12^3 , and k = 12.



  1. k = 2.
    D௘ͽ V = 20k^3  Â IW^3.
    E௘ͽ Vbottom í IW^3.




  2. D௘ͽ k   20 5 ͼ௘RUk (^5) ௘ͽ
    E௘ͽ k^2 1625.
    F௘ͽ k^2 1625.
    G௘ͽ 6XSSRVHWKDWWKHODWHUDODUHDRIWKHWRSFRQHLVA.
    Then, the lateral area of the entire cone is 25 9 Ak^2 1625 A, so the lateral area of the bottom portion is
    16 AA 16 A.^
    The ratio of the two lateral areas, top over bottom, is 9 169.
    16




A


A^


H௘ͽ 6XSSRVHWKDWWKHYROXPHRIWKHWRSFRQHLVV.
Then, the volume of the entire cone is 125 61 Vk^3 125 V, so the volume of the bottom portion is
VV V.^
The ratio of the two volumes, top over bottom, is 61  61.


V


V^

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