1. The problem asks to find the exact value of the sine ratio for the angle of 1.5 radians in standard position. 2. Recall that the sine of an angle in standard position on the unit circle is the y-coordinate of the point where the terminal side of the angle intersects the unit circle. 3. Since 1.5 radians is not a special angle with a commonly memorized sine value, we use the sine function directly: $\sin(1.5)$. 4. The sine function is defined for all real numbers, and for 1.5 radians, the value can be found using a calculator or sine tables. 5. Using a calculator, $\sin(1.5) \approx 0.997494$. 6. Therefore, the exact value of the sine ratio for the angle 1.5 radians is approximately $0.9975$ (rounded to four decimal places).