Difference between revisions of "Mock AIME 1 2007-2008 Problems/Problem 11"
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== Solution == | == Solution == | ||
− | + | <center><asy> | |
− | {{ | + | size(150); defaultpen(linewidth(0.8)); import markers; |
+ | pair B = (0,0), C = (25,0), A = (578/50,19.8838); | ||
+ | draw(A--B--C--cycle); | ||
+ | label("$B$",B,SW); label("$C$",C,SE); label("$A$",A,N); | ||
+ | pair D = (13,0), E = (11*A + 13*C)/24, F = (12*B + 11*A)/23; | ||
+ | draw(D--E--F--cycle); | ||
+ | label("$D$",D,dir(-90)); | ||
+ | label("$E$",E,dir(0)); | ||
+ | label("$F$",F,dir(180)); | ||
+ | |||
+ | draw(A--E,StickIntervalMarker(1,3,size=6));draw(B--D,StickIntervalMarker(1,3,size=6)); | ||
+ | draw(F--B,StickIntervalMarker(1,2,size=6)); draw(E--C,StickIntervalMarker(1,2,size=6)); | ||
+ | draw(A--F,StickIntervalMarker(1,1,size=6)); draw(C--D,StickIntervalMarker(1,1,size=6)); | ||
+ | |||
+ | label("24",A--C,5*dir(0)); label("25",B--C,5*dir(-90)); label("23",B--A,5*dir(180)); | ||
+ | </asy></center> | ||
+ | |||
+ | From adjacent sides, the following relationships can be derived: | ||
+ | |||
+ | <cmath>\begin{align*} | ||
+ | DC &= EC + 1\ | ||
+ | AE &= AF + 1\ | ||
+ | BD &= BF + 2 | ||
+ | \end{align*}</cmath> | ||
+ | |||
+ | Since <math>BF = EC</math>, and <math>DC = BF + 1</math>, <math>BD = DC + 1</math>. Thus, <math>BC = BD + DC = BD + (BD - 1)</math>. <math>26 = 2BD</math>. Thus, <math>BD = 13/1</math>. Thus, the answer is <math>\boxed{014}</math>. | ||
== See also == | == See also == |
Latest revision as of 19:02, 29 January 2020
Problem
is inscribed inside such that lie on , respectively. The circumcircles of have centers , respectively. Also, , and . The length of can be written in the form , where and are relatively prime integers. Find .
Solution
From adjacent sides, the following relationships can be derived:
Since , and , . Thus, . . Thus, . Thus, the answer is .
See also
Mock AIME 1 2007-2008 (Problems, Source) | ||
Preceded by Problem 10 |
Followed by Problem 12 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 |