2017 UNCO Math Contest II Problems/Problem 1


[asy] pair A=24*dir(40),B=15*dir(220); pair C1=(0,0),C2=(52,0);  draw(circle(C1,24),black); draw(circle(C2,15),black);  draw(C1--C2,dot); draw(A--(B+C2)); [/asy]

A circle has radius 24, a second circle has radius 15, and the centers of the two circles are 52 units apart. A line tangent to both circles crosses the line connecting the two centers at a point P between the two centers. How much farther is P from the center of the bigger circle than it is from the center of the smaller circle?



[asy] pair A=24*dir(40), B=15*dir(220); pair C1=(0,0),C2=(52,0); pair [] x=intersectionpoints(C1--C2, A--(B+C2)); pair P=x[0];  draw(circle(C1,24),black); draw(circle(C2,15),black);  draw(C1--C2,dot); draw(A--(B+C2), dot); draw(P--P, dot); draw(C1--A); draw(C2--(B+C2));  label("A",A,NE); label("B",B+C2,SW); label("O1",C1,S); label("O2",C2,N); label("P",P,SW); [/asy]

Solution 1

By similar triangles, $O_1P$ is $\frac{24}{39}\cdot 52$ and $O_2P$ is $\frac{15}{39}*52$. Their difference is $\frac{9}{39}\cdot 52$, or $\boxed{12}$

See also

2017 UNCO Math Contest II (ProblemsAnswer KeyResources)
Preceded by
First Question
Followed by
Problem 2
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All UNCO Math Contest Problems and Solutions