A, O e O1 são colineares e A,O e T são colineares, portanto A,O,T and O1 são colineares.
[tex3]∠O1AL=60^∘ e ~ O1A=O1L=R \implies △O1AL (equilátero)\\
LT=\frac{R\sqrt3}{2}⟹TE=\frac{R}{2\sqrt3}\\
OT=\frac{R}{2}−r\\
OT^2+TE^2=OE^2⟹(\frac{R}{2}−r)^2+(\frac{R}{2\sqrt3})^2=r^2 \implies\\
R=3r\\
TE^=\frac{R^2}{12}=10(R−r)=\frac{20R}{3}.\\
∴\boxed{\color{red}R=80}[/tex3]...