Difference between revisions of "1960 AHSME Problems/Problem 21"

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==Problem==
 
==Problem==
  
The diagonal of square <math>I</math> is <math>a+b</math>. The perimeter of square <math>II</math> with twice the area of <math>I</math> is:
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The diagonal of square <math>I</math> is <math>a+b</math>. The area of square <math>II</math> with twice the area of <math>I</math> is:
  
 
<math>\textbf{(A)}\ (a+b)^2\qquad
 
<math>\textbf{(A)}\ (a+b)^2\qquad
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==See Also==
 
==See Also==
 
{{AHSME 40p box|year=1960|num-b=20|num-a=22}}
 
{{AHSME 40p box|year=1960|num-b=20|num-a=22}}
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[[Category:Introductory Geometry Problems]]

Latest revision as of 02:00, 1 February 2024

Problem

The diagonal of square $I$ is $a+b$. The area of square $II$ with twice the area of $I$ is:

$\textbf{(A)}\ (a+b)^2\qquad \textbf{(B)}\ \sqrt{2}(a+b)^2\qquad \textbf{(C)}\ 2(a+b)\qquad \textbf{(D)}\ \sqrt{8}(a+b) \qquad \textbf{(E)}\ 4(a+b)$

Solution

Since the diagonal of square $I$ is $a+b$ units long, the side length of square $I$ is $\frac{a+b}{\sqrt{2}}$, so the area of square $I$ is $\frac{(a+b)^2}{2}$.

The area of square $II$ is twice as much as the area of square $I$, so the area of square $II$ is $(a+b)^2$. That means the side length of square $II$ is $a+b$, so the perimeter of square $II$ is $4(a+b)$, or answer choice $\boxed{\textbf{(E)}}$.

See Also

1960 AHSC (ProblemsAnswer KeyResources)
Preceded by
Problem 20
Followed by
Problem 22
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All AHSME Problems and Solutions