Finding the Fourth Proportional to 1,145.91, 1,581.12 and 648.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.91 : 1,581.12 = 648.57 : x
2. Step 2: Convert to fraction form
   1,145.91/1,581.12 = 648.57/x
3. Step 3: Cross multiply
   1,145.91x = 1,581.12 × 648.57
4. Step 4: Simplify right side
   1,145.91x = 1,025,467.00
5. Step 5: Solve for x
   x = 1,025,467.00/1,145.91
6. Step 6: Final answer
   x = 894.89