1. **State the problem:** We have three congruent rectangles arranged so that each is rotated 90° around a vertex of the previous rectangle. Given points A(2,5) and B(4,1.5), find coordinates of points C and D. 2. **Understand the rotation:** A 90° rotation around a point $(x_0,y_0)$ transforms a point $(x,y)$ to $(x_0 - (y - y_0), y_0 + (x - x_0))$ when rotating counterclockwise. 3. **Find vector from A to B:** $$\vec{AB} = (4 - 2, 1.5 - 5) = (2, -3.5)$$ 4. **Find point C by rotating B 90° around A:** Using the formula: $$C_x = 2 - (1.5 - 5) = 2 - (-3.5) = 5.5$$ $$C_y = 5 + (4 - 2) = 5 + 2 = 7$$ So, $C = (5.5, 7)$. 5. **Find point D by rotating A 90° around B:** Using the formula: $$D_x = 4 - (5 - 1.5) = 4 - 3.5 = 0.5$$ $$D_y = 1.5 + (2 - 4) = 1.5 - 2 = -0.5$$ So, $D = (0.5, -0.5)$. **Final answer:** $$C = (5.5, 7), \quad D = (0.5, -0.5)$$