homework and exercises - Resistances in a circular loop

I have no idea what formula I'm supposed to use.I just want to know the concept that would allow me to get the answer. I know basic concepts of electricity like charge, currents, etc., but as far resistances go I know only about series and parallel. I tried looking for resistances in a circular loop but I didn't understand what was being explained. Also I didn't find any concept that helped me understand what was to be done, probably because I didn't understand them.I used some help from a different question and got the resistances but my answer wasnt correct.

Answer

Resistance can be taken as

$$R = \rho \frac{l}{a}$$ where $rho$ is resistivity, $l$ is length of resistor and $a$ is cross sectional area of the resistor.

The above is asking you for a ratio of $R_1:R_2$ and you are given all the numbers in the question. Shapes within a circuit diagram can typically be ignored, the diagrams are only symbolic to inform you of how the pieces are connected.