Difference between revisions of "1964 AHSME Problems/Problem 38"

(Solution)
Line 6: Line 6:
  
 
==Solution==
 
==Solution==
 +
By the [[Median Formula]], <math>PM = \frac12\sqrt{2PQ^2+2PR^2-QR^2}</math>
  
 +
Plugging in the numbers given in the problem, we get
 +
<cmath>\frac72=\frac12\sqrt{2\cdot4^2+2\cdot7^2-QR^2</cmath>
  
 
==See Also==
 
==See Also==

Revision as of 18:14, 9 March 2020

Problem

The sides $PQ$ and $PR$ of triangle $PQR$ are respectively of lengths $4$ inches, and $7$ inches. The median $PM$ is $3\frac{1}{2}$ inches. Then $QR$, in inches, is:

$\textbf{(A) }6\qquad\textbf{(B) }7\qquad\textbf{(C) }8\qquad\textbf{(D) }9\qquad \textbf{(E) }10$

Solution

By the Median Formula, $PM = \frac12\sqrt{2PQ^2+2PR^2-QR^2}$

Plugging in the numbers given in the problem, we get

\[\frac72=\frac12\sqrt{2\cdot4^2+2\cdot7^2-QR^2\] (Error compiling LaTeX. Unknown error_msg)

See Also

1964 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 37
Followed by
Problem 39
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