Finding the Fourth Proportional to 1,141.11, 1,574.71 and 643.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.11 : 1,574.71 = 643.72 : x
2. Step 2: Convert to fraction form
   1,141.11/1,574.71 = 643.72/x
3. Step 3: Cross multiply
   1,141.11x = 1,574.71 × 643.72
4. Step 4: Simplify right side
   1,141.11x = 1,013,672.32
5. Step 5: Solve for x
   x = 1,013,672.32/1,141.11
6. Step 6: Final answer
   x = 888.32