1. The problem is to understand the 4 quadrants in a 360-degree circle and how to mark each quadrant with its degree range. 2. A circle is divided into 360 degrees, and the four quadrants split this circle into four equal parts of 90 degrees each. 3. The quadrants are numbered counterclockwise starting from the positive x-axis (0 degrees). 4. Quadrant I covers from $0^\circ$ to $90^\circ$, Quadrant II from $90^\circ$ to $180^\circ$, Quadrant III from $180^\circ$ to $270^\circ$, and Quadrant IV from $270^\circ$ to $360^\circ$. 5. Each quadrant corresponds to a specific range of angles and is used in trigonometry and coordinate geometry to locate points. 6. The formula for the degree range of each quadrant is $\text{Quadrant } n = [(n-1) \times 90^\circ, n \times 90^\circ]$ for $n=1,2,3,4$. 7. Understanding these quadrants helps in analyzing the signs of sine and cosine functions in each quadrant. Final answer: The circle is divided into 4 quadrants each spanning 90 degrees: - Quadrant I: $0^\circ$ to $90^\circ$ - Quadrant II: $90^\circ$ to $180^\circ$ - Quadrant III: $180^\circ$ to $270^\circ$ - Quadrant IV: $270^\circ$ to $360^\circ$