1. **Problem statement:** Given the number line with points B at -3, O at 0, I at 1, and A at 4, and the line $\Delta$ defined by points (0, I). 2. **Part (a):** - The line $\Delta$ passes through points 0 and I (which is at 1). - The coordinate of point A is $4$. - The coordinate of point B is $-3$. 3. **Part (b):** - Find points E and F such that their coordinates are $\frac{5}{2} = 2.5$ and $-1.5$ respectively. 4. **Part (c):** - Arrange the coordinates of points A, B, E, and F in ascending order. **Step-by-step solution:** 1. The coordinate of A is given as $4$. 2. The coordinate of B is given as $-3$. 3. The coordinate of E is $2.5$. 4. The coordinate of F is $-1.5$. 5. To arrange these in ascending order, list them from smallest to largest: $$-3 < -1.5 < 2.5 < 4$$ So the order is: B, F, E, A. --- **Final answers:** - Coordinate of A: $4$ - Coordinate of B: $-3$ - Coordinates of E and F: $2.5$ and $-1.5$ respectively - Ascending order of coordinates: $-3, -1.5, 2.5, 4$ corresponding to points B, F, E, A respectively.