10. The locus of the center of a circle with radius $1 \mathrm{~cm}$ that is internally tangent to a circle with radius $1,5 \mathrm{~cm}$ is
10. A circle with a radius of $1.5 \mathrm{~cm}$, and a circle with a radius of $0.5 \mathrm{~cm}$, both centered at the same point.