Chapter 23 - Mirrors and Lenses - Learning Path Questions and Exercises - Exercises - Page 806: 17

So the image is real, inverted and same size as the object.

$do=R=2f$ or, $\frac{1}{do}+\frac{1}{di}=\frac{1}{f}$ or, $\frac{1}{2f}+\frac{1}{di}=\frac{1}{f}$ or, $di=2f$ Thus, $M=|\frac{2f}{2f}|=1$ Hence, the size of image is same but inverted. So the image is real, inverted and same size as the object.