Difference between revisions of "1963 AHSME Problems/Problem 10"

(Solution to Problem 10)
 
m (Problem 10)
 
Line 1: Line 1:
== Problem 10==
+
== Problem ==
  
 
Point <math>P</math> is taken interior to a square with side-length <math>a</math> and such that is it equally distant from two  
 
Point <math>P</math> is taken interior to a square with side-length <math>a</math> and such that is it equally distant from two  
Line 8: Line 8:
 
\textbf{(C)}\ \frac{3a}{8}\qquad
 
\textbf{(C)}\ \frac{3a}{8}\qquad
 
\textbf{(D)}\ \frac{a\sqrt{2}}{2}\qquad
 
\textbf{(D)}\ \frac{a\sqrt{2}}{2}\qquad
\textbf{(E)}\ \frac{a}{2} </math>  
+
\textbf{(E)}\ \frac{a}{2} </math>
  
 
==Solution==
 
==Solution==

Latest revision as of 08:22, 5 June 2018

Problem

Point $P$ is taken interior to a square with side-length $a$ and such that is it equally distant from two consecutive vertices and from the side opposite these vertices. If $d$ represents the common distance, then $d$ equals:

$\textbf{(A)}\ \frac{3a}{5}\qquad \textbf{(B)}\ \frac{5a}{8}\qquad \textbf{(C)}\ \frac{3a}{8}\qquad \textbf{(D)}\ \frac{a\sqrt{2}}{2}\qquad \textbf{(E)}\ \frac{a}{2}$

Solution

[asy] draw((0,0)--(16,0)--(16,16)--(0,16)--(0,0)); draw((0,0)--(8,6)); draw((16,0)--(8,6)); draw((8,16)--(8,6)); draw((8,0)--(8,6),dotted); label("$d$",(4,3),NW); label("$d$",(12,3),NE); label("$d$",(8,11),W); label("$\frac{a}{2}$",(4,0),S); label("$\frac{a}{2}$",(12,0),S); label("$a-d$",(8,2),W); [/asy] Draw a diagram and label it as shown. Because of SSS Congruency, the two bottom triangles are right triangles. By the Pythagorean Theorem, \[d^2 = (a-d)^2 + (\frac{a}{2})^2\] \[d^2 = a^2 - 2ad + d^2 + \frac{a^2}{4}\] \[2ad = \frac{5a^2}{4}\] \[d = \frac{5a}{8}\] Thus, the answer is $\boxed{\textbf{(B)}}$.

See Also

1963 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 9
Followed by
Problem 11
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
All AHSME Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. AMC logo.png