Difference between revisions of "1986 AHSME Problems/Problem 18"

(Created page with "==Problem== A plane intersects a right circular cylinder of radius <math>1</math> forming an ellipse. If the major axis of the ellipse of <math>50\%</math> longer than the mino...")
 
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A plane intersects a right circular cylinder of radius <math>1</math> forming an ellipse.  
 
A plane intersects a right circular cylinder of radius <math>1</math> forming an ellipse.  
If the major axis of the ellipse of <math>50\%</math> longer than the minor axis, the length of the major axis is
+
If the major axis of the ellipse is <math>50\%</math> longer than the minor axis, the length of the major axis is
  
 
<math>\textbf{(A)}\ 1\qquad
 
<math>\textbf{(A)}\ 1\qquad
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\textbf{(C)}\ 2\qquad
 
\textbf{(C)}\ 2\qquad
 
\textbf{(D)}\ \frac{9}{4}\qquad
 
\textbf{(D)}\ \frac{9}{4}\qquad
\textbf{(E)}\ 3  </math>
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\textbf{(E)}\ 3  </math>
  
 
==Solution==
 
==Solution==
  
 +
We note that we can draw the minor axis to see that because the minor axis is the minimum distance between two opposite points on the ellipse, we can draw a line through two opposite points of the cylinder, and so the minor axis is <math>2(1) = 2</math>. Therefore, our answer is <math>2(1.5) = 3</math>, and so our answer is <math>\boxed{E}</math>.
  
 
== See also ==
 
== See also ==

Latest revision as of 18:31, 12 October 2023

Problem

A plane intersects a right circular cylinder of radius $1$ forming an ellipse. If the major axis of the ellipse is $50\%$ longer than the minor axis, the length of the major axis is

$\textbf{(A)}\ 1\qquad \textbf{(B)}\ \frac{3}{2}\qquad \textbf{(C)}\ 2\qquad \textbf{(D)}\ \frac{9}{4}\qquad \textbf{(E)}\ 3$

Solution

We note that we can draw the minor axis to see that because the minor axis is the minimum distance between two opposite points on the ellipse, we can draw a line through two opposite points of the cylinder, and so the minor axis is $2(1) = 2$. Therefore, our answer is $2(1.5) = 3$, and so our answer is $\boxed{E}$.

See also

1986 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 17
Followed by
Problem 19
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