Difference between revisions of "2023 AMC 10B Problems/Problem 17"

(Solution)
Line 43: Line 43:
 
draw(CC--DD);
 
draw(CC--DD);
  
 +
 +
label("a",midpoint(D--DD),E);
 +
label("b",midpoint(CC--DD),E);
 +
label("c",midpoint(AA--CC),S);
 
</asy>
 
</asy>
  
Line 48: Line 52:
  
 
<cmath>\begin{align*}
 
<cmath>\begin{align*}
   \sqrt{a^+b^2+c^2}&=
+
   \sqrt{a^2+b^2+c^2}&=\sqrt{(a+b+c)^2-2(ab+bc+ca)}\\
 +
&=\sqrt{(\dfrac{13}{4})^2-\dfrac{11}{2}}\\
 +
&=\dfrac{9}{4}
 
\end{align*}
 
\end{align*}
 
</cmath>
 
</cmath>
  
 
~Technodoggo
 
~Technodoggo

Revision as of 15:09, 15 November 2023

Solution

[asy] import geometry; pair A = (-3, 4); pair B = (-3, 5); pair C = (-1, 4); pair D = (-1, 5);   pair AA = (0, 0); pair BB = (0, 1); pair CC = (2, 0); pair DD = (2, 1);     draw(D--AA,dashed);  draw(A--B); draw(A--C); draw(B--D); draw(C--D);  draw(A--AA); draw(B--BB); draw(C--CC); draw(D--DD);  // Dotted vertices dot(A); dot(B); dot(C); dot(D);    dot(AA); dot(BB); dot(CC); dot(DD);  draw(AA--BB); draw(AA--CC); draw(BB--DD); draw(CC--DD);   label("a",midpoint(D--DD),E); label("b",midpoint(CC--DD),E); label("c",midpoint(AA--CC),S); [/asy]

The diagonal of the box is

\begin{align*}    \sqrt{a^2+b^2+c^2}&=\sqrt{(a+b+c)^2-2(ab+bc+ca)}\\ &=\sqrt{(\dfrac{13}{4})^2-\dfrac{11}{2}}\\ &=\dfrac{9}{4} \end{align*}

~Technodoggo