[asy] import graph; size(7.99cm);  real labelscalefactor = 0.5;  pen dps = linewidth(0.7) + fontsize(10); defaultpen(dps); pen dotstyle = black;  real xmin = 4.087153740193288, xmax = 11.08175859031552, ymin = -4.938019122704778, ymax = 1.194137062512079;  draw(circle((7.780000000000009,-1.320000000000002), 2.000000000000000));  draw(circle((7.271934046987930,-1.319179731427737), 1.491933384829670));  draw(circle((9.198812158392690,-0.8249788848962227), 0.4973111282761416));  draw((5.780002606580324,-1.316771019595571)--(9.779997393419690,-1.323228980404432));  draw((9.198812158392690,-0.8249788848962227)--(9.198009254448635,-1.322289365031666));  draw((7.271934046987930,-1.319179731427737)--(9.198812158392690,-0.8249788848962227));  draw((9.198812158392690,-0.8249788848962227)--(7.780000000000009,-1.320000000000002));  dot((7.780000000000009,-1.320000000000002),dotstyle);  label("$C$", (7.707377218471464,-1.576266740352400), NE * labelscalefactor);  dot((7.271934046987930,-1.319179731427737),dotstyle);  label("$D$", (7.303064016111554,-1.276266740352400), NE * labelscalefactor);  dot((9.198812158392690,-0.8249788848962227),dotstyle);  label("$E$", (9.225301294671791,-0.7792624249832147), NE * labelscalefactor);  dot((9.198009254448635,-1.322289365031666),dotstyle);  label("$F$", (9.225301294671791,-1.276266740352400), NE * labelscalefactor);  dot((9.779997393419690,-1.323228980404432),dotstyle);  label("$B$", (9.810012253929656,-1.276266740352400), NE * labelscalefactor);  dot((5.780002606580324,-1.316771019595571),dotstyle);  label("$A$", (5.812051070003994,-1.276266740352400), NE * labelscalefactor);  clip((xmin,ymin)--(xmin,ymax)--(xmax,ymax)--(xmax,ymin)--cycle); [/asy]
Using the diagram above, let the radius of $D$ be $3r$, and the radius of $E$ be $r$. Then, $EF=r$, and $CE=2-r$, so the Pythagorean theorem in $\triangle CEF$ gives $CF=\sqrt{4-4r}$. Also, $CD=CA-AD=2-3r$, so\[DF=DC+CF=2-3r+\sqrt{4-4r}.\]Noting that $DE=4r$, we can now use the Pythagorean theorem in $\triangle DEF$ to get\[(2-3r+\sqrt{4-4r})^2+r^2=16r^2.\]
Solving this quadratic is somewhat tedious, but the constant terms cancel, so the computation isn't terrible. Solving gives $3r=\sqrt{240}-14$ for a final answer of $254$.
Notice that C, E and the point of tangency to circle C for circle E will be concurrent because C and E intersect the tangent line at a right angle, implying they must be on the same line.
[asy] import graph; size(7.99cm); real labelscalefactor = 0.5; pen dps = linewidth(0.7) + fontsize(10); defaultpen(dps); pen dotstyle = black; real xmin = 4.087153740193288, xmax = 11.08175859031552, ymin = -4.938019122704778, ymax = 1.194137062512079; draw(circle((7.780000000000009,-1.320000000000002), 2.000000000000000)); draw(circle((7.271934046987930,-1.319179731427737), 1.491933384829670)); draw(circle((9.198812158392690,-0.8249788848962227), 0.4973111282761416)); draw((5.780002606580324,-1.316771019595571)--(9.779997393419690,-1.323228980404432)); draw((9.198812158392690,-0.8249788848962227)--(9.198009254448635,-1.322289365031666)); draw((7.271934046987930,-1.319179731427737)--(9.198812158392690,-0.8249788848962227)); draw((9.198812158392690,-0.8249788848962227)--(7.780000000000009,-1.320000000000002)); dot((7.780000000000009,-1.320000000000002),dotstyle); label("$C$", (7.707377218471464,-1.576266740352400), NE * labelscalefactor); dot((7.271934046987930,-1.319179731427737),dotstyle); label("$D$", (7.303064016111554,-1.276266740352400), NE * labelscalefactor); dot((9.198812158392690,-0.8249788848962227),dotstyle); label("$E$", (9.225301294671791,-0.7792624249832147), NE * labelscalefactor); dot((9.198009254448635,-1.322289365031666),dotstyle); label("$F$", (9.225301294671791,-1.276266740352400), NE * labelscalefactor); dot((9.779997393419690,-1.323228980404432),dotstyle); label("$B$", (9.810012253929656,-1.276266740352400), NE * labelscalefactor); dot((5.780002606580324,-1.316771019595571),dotstyle); label("$A$", (5.812051070003994,-1.276266740352400), NE * labelscalefactor); clip((xmin,ymin)--(xmin,ymax)--(xmax,ymax)--(xmax,ymin)--(xmax,ymin)--cycle); [/asy]
위의 다이어그램을 사용하여 $D$의 반지름을 $3r$로 하고 $E$의 반지름을 $r$로 합니다. 그러면 $EF=r$이고 $CE=2-r$이므로 $\삼각형 CEF$의 피타고라스 정리는 $CF=\sqrt{4-4r}$가 됩니다. 또한 $CD=CA-AD=2-3r$이므로 \[DF=DC+CF=2-3r+\sqrt{4-4r}.\]$DE=4r$에 주목하면 이제 $\삼각형 DEF$에서 피타고라스 정리를 사용하여 \[(2-3r+\sqrt{4-4r})^2+r^2=16r^2\]를 구할 수 있습니다.
이 이차방정식을 푸는 것은 다소 지루하지만 상수 항이 상쇄되므로 계산이 나쁘지 않습니다. 풀면 $3r=\sqrt{240}-14$로 최종 답은 $254$가 됩니다.
C와 E가 접선과 직각으로 교차하기 때문에 C, E, 원 E에 대한 원 C의 접점은 동시에 존재하며, 이는 같은 선상에 있어야 함을 의미합니다.