Finding the Fourth Proportional to 1,141.10, 1,574.72 and 643.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.10 : 1,574.72 = 643.85 : x
2. Step 2: Convert to fraction form
   1,141.10/1,574.72 = 643.85/x
3. Step 3: Cross multiply
   1,141.10x = 1,574.72 × 643.85
4. Step 4: Simplify right side
   1,141.10x = 1,013,884.32
5. Step 5: Solve for x
   x = 1,013,884.32/1,141.10
6. Step 6: Final answer
   x = 888.51