1. The problem is to clarify whether counting angles from $C270$ starts at 0 or 1. 2. In angle measurement, counting always starts at 0 degrees (or radians), representing the initial position. 3. When you say "counting from $C270$," it means you treat $270^\circ$ as your new zero point. 4. So, you start counting angles at 0 from $270^\circ$, not at 1. 5. This is similar to resetting your angle scale so that $270^\circ$ becomes 0, and then you count upwards from there. 6. Therefore, the count starts at 0, not 1, when measuring angles from $C270$. Final answer: You start counting at 0, not 1, when counting angles from $C270$.