Difference between revisions of "2004 AMC 12B Problems/Problem 6"

m (Problem)
m (Solution)
Line 8: Line 8:
 
== Solution ==
 
== Solution ==
  
The directions "southwest" and "southeast" are orthogonal. Thus the described situation is a right triangle with legs 8 miles and 10 miles long. The hypotenuse length is <math>\sqrt{8^2 + 10^2} \sim 12.8</math>, and thus the answer is <math>\mathrm{(A)}</math>.
+
The directions "southwest" and "southeast" are orthogonal. Thus the described situation is a right triangle with legs <math>8</math> miles and <math>10</math> miles long. The hypotenuse length is <math>\sqrt{8^2 + 10^2}\approx12.8</math>, and thus the answer is <math>\boxed{\mathrm{(A)}\ 13}</math>.
  
Without a calculator one can note that <math>8^2 + 10^2 = 164 < 169 = 13^2\rightarrow\boxed{A}</math>.
+
Without a calculator one can note that <math>8^2+10^2=164<169=13^2\Rightarrow\boxed{\mathrm{(A)}\ 13}</math>.
  
 
== See Also ==
 
== See Also ==

Revision as of 21:31, 22 July 2014

The following problem is from both the 2004 AMC 12B #6 and 2004 AMC 10B #8, so both problems redirect to this page.

Problem

Minneapolis-St. Paul International Airport is $8$ miles southwest of downtown St. Paul and $10$ miles southeast of downtown Minneapolis. Which of the following is closest to the number of miles between downtown St. Paul and downtown Minneapolis?

$\mathrm{(A)\ }13\qquad\mathrm{(B)\ }14\qquad\mathrm{(C)\ }15\qquad\mathrm{(D)\ }16\qquad\mathrm{(E)\ }17$

Solution

The directions "southwest" and "southeast" are orthogonal. Thus the described situation is a right triangle with legs $8$ miles and $10$ miles long. The hypotenuse length is $\sqrt{8^2 + 10^2}\approx12.8$, and thus the answer is $\boxed{\mathrm{(A)}\ 13}$.

Without a calculator one can note that $8^2+10^2=164<169=13^2\Rightarrow\boxed{\mathrm{(A)}\ 13}$.

See Also

2004 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 5
Followed by
Problem 7
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
All AMC 12 Problems and Solutions
2004 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 7
Followed by
Problem 9
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
All AMC 10 Problems and Solutions

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