Difference between revisions of "1987 AIME Problems/Problem 2"

(apparently the 5 is supposed to be positive, solution)
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== Problem ==
 
== Problem ==
What is the largest possible [[distance]] between two [[point]]s, one on the [[sphere]] of [[radius]] 19 with [[center]] <math>\displaystyle (-2,-10,5)</math> and the other on the sphere of radius 87 with center <math>\displaystyle (12,8,-16)</math>?
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What is the largest possible [[distance]] between two [[point]]s, one on the [[sphere]] of [[radius]] 19 with [[center]] <math>(-2,-10,5)</math> and the other on the sphere of radius 87 with center <math>(12,8,-16)</math>?
  
 
== Solution ==
 
== Solution ==
The distance between the two centers of the spheres can be determined via the [[distance formula]] in three dimensions: <math>\sqrt{(12 - (-2))^2 + (8 - (-10))^2 + (-16 - 5)^2} = \sqrt{14^2 + 18^2 + 21^2} = 31</math>. The largest possible distance would be the sum of the two radii and the distance between the two centers, making it <math>19 + 87 + 31 = 137</math>.
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The distance between the two centers of the spheres can be determined via the [[distance formula]] in three dimensions: <math>\sqrt{(12 - (-2))^2 + (8 - (-10))^2 + (-16 - 5)^2} = \sqrt{14^2 + 18^2 + 21^2} = 31</math>. The largest possible distance would be the sum of the two radii and the distance between the two centers, making it <math>19 + 87 + 31 = \boxed{137}</math>.
  
 
== See also ==
 
== See also ==
 
{{AIME box|year=1987|num-b=1|num-a=3}}
 
{{AIME box|year=1987|num-b=1|num-a=3}}
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{{MAA Notice}}

Latest revision as of 17:46, 14 February 2014

Problem

What is the largest possible distance between two points, one on the sphere of radius 19 with center $(-2,-10,5)$ and the other on the sphere of radius 87 with center $(12,8,-16)$?

Solution

The distance between the two centers of the spheres can be determined via the distance formula in three dimensions: $\sqrt{(12 - (-2))^2 + (8 - (-10))^2 + (-16 - 5)^2} = \sqrt{14^2 + 18^2 + 21^2} = 31$. The largest possible distance would be the sum of the two radii and the distance between the two centers, making it $19 + 87 + 31 = \boxed{137}$.

See also

1987 AIME (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
All AIME Problems and Solutions

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